diff --git a/english2_test_120s_16k.wav b/dev/english2_test_120s_16k.wav
similarity index 100%
rename from english2_test_120s_16k.wav
rename to dev/english2_test_120s_16k.wav
diff --git a/english2_test_15s_16k.wav b/dev/english2_test_15s_16k.wav
similarity index 100%
rename from english2_test_15s_16k.wav
rename to dev/english2_test_15s_16k.wav
diff --git a/english2_test_180s_16k.wav b/dev/english2_test_180s_16k.wav
similarity index 100%
rename from english2_test_180s_16k.wav
rename to dev/english2_test_180s_16k.wav
diff --git a/english2_test_240s_16k.wav b/dev/english2_test_240s_16k.wav
similarity index 100%
rename from english2_test_240s_16k.wav
rename to dev/english2_test_240s_16k.wav
diff --git a/english2_test_300s_16k.wav b/dev/english2_test_300s_16k.wav
similarity index 100%
rename from english2_test_300s_16k.wav
rename to dev/english2_test_300s_16k.wav
diff --git a/english2_test_30s_16k.wav b/dev/english2_test_30s_16k.wav
similarity index 100%
rename from english2_test_30s_16k.wav
rename to dev/english2_test_30s_16k.wav
diff --git a/english2_test_45s_16k.wav b/dev/english2_test_45s_16k.wav
similarity index 100%
rename from english2_test_45s_16k.wav
rename to dev/english2_test_45s_16k.wav
diff --git a/english2_test_60s_16k.wav b/dev/english2_test_60s_16k.wav
similarity index 100%
rename from english2_test_60s_16k.wav
rename to dev/english2_test_60s_16k.wav
diff --git a/english_test_120s_16k.wav b/dev/english_test_120s_16k.wav
similarity index 100%
rename from english_test_120s_16k.wav
rename to dev/english_test_120s_16k.wav
diff --git a/english_test_15s_16k.wav b/dev/english_test_15s_16k.wav
similarity index 100%
rename from english_test_15s_16k.wav
rename to dev/english_test_15s_16k.wav
diff --git a/english_test_180s_16k.wav b/dev/english_test_180s_16k.wav
similarity index 100%
rename from english_test_180s_16k.wav
rename to dev/english_test_180s_16k.wav
diff --git a/english_test_240s_16k.wav b/dev/english_test_240s_16k.wav
similarity index 100%
rename from english_test_240s_16k.wav
rename to dev/english_test_240s_16k.wav
diff --git a/english_test_30s_16k.wav b/dev/english_test_30s_16k.wav
similarity index 100%
rename from english_test_30s_16k.wav
rename to dev/english_test_30s_16k.wav
diff --git a/english_test_45s_16k.wav b/dev/english_test_45s_16k.wav
similarity index 100%
rename from english_test_45s_16k.wav
rename to dev/english_test_45s_16k.wav
diff --git a/english_test_60s_16k.wav b/dev/english_test_60s_16k.wav
similarity index 100%
rename from english_test_60s_16k.wav
rename to dev/english_test_60s_16k.wav
diff --git a/french_test_120s_16k.wav b/dev/french_test_120s_16k.wav
similarity index 100%
rename from french_test_120s_16k.wav
rename to dev/french_test_120s_16k.wav
diff --git a/french_test_15s_16k.wav b/dev/french_test_15s_16k.wav
similarity index 100%
rename from french_test_15s_16k.wav
rename to dev/french_test_15s_16k.wav
diff --git a/french_test_180s_16k.wav b/dev/french_test_180s_16k.wav
similarity index 100%
rename from french_test_180s_16k.wav
rename to dev/french_test_180s_16k.wav
diff --git a/french_test_240s_16k.wav b/dev/french_test_240s_16k.wav
similarity index 100%
rename from french_test_240s_16k.wav
rename to dev/french_test_240s_16k.wav
diff --git a/french_test_300s_16k.wav b/dev/french_test_300s_16k.wav
similarity index 100%
rename from french_test_300s_16k.wav
rename to dev/french_test_300s_16k.wav
diff --git a/french_test_30s_16k.wav b/dev/french_test_30s_16k.wav
similarity index 100%
rename from french_test_30s_16k.wav
rename to dev/french_test_30s_16k.wav
diff --git a/french_test_45s_16k.wav b/dev/french_test_45s_16k.wav
similarity index 100%
rename from french_test_45s_16k.wav
rename to dev/french_test_45s_16k.wav
diff --git a/french_test_60s_16k.wav b/dev/french_test_60s_16k.wav
similarity index 100%
rename from french_test_60s_16k.wav
rename to dev/french_test_60s_16k.wav
diff --git a/hindi_test_120s_16k.wav b/dev/hindi_test_120s_16k.wav
similarity index 100%
rename from hindi_test_120s_16k.wav
rename to dev/hindi_test_120s_16k.wav
diff --git a/hindi_test_15s_16k.wav b/dev/hindi_test_15s_16k.wav
similarity index 100%
rename from hindi_test_15s_16k.wav
rename to dev/hindi_test_15s_16k.wav
diff --git a/hindi_test_180s_16k.wav b/dev/hindi_test_180s_16k.wav
similarity index 100%
rename from hindi_test_180s_16k.wav
rename to dev/hindi_test_180s_16k.wav
diff --git a/hindi_test_240s_16k.wav b/dev/hindi_test_240s_16k.wav
similarity index 100%
rename from hindi_test_240s_16k.wav
rename to dev/hindi_test_240s_16k.wav
diff --git a/hindi_test_300s_16k.wav b/dev/hindi_test_300s_16k.wav
similarity index 100%
rename from hindi_test_300s_16k.wav
rename to dev/hindi_test_300s_16k.wav
diff --git a/hindi_test_30s_16k.wav b/dev/hindi_test_30s_16k.wav
similarity index 100%
rename from hindi_test_30s_16k.wav
rename to dev/hindi_test_30s_16k.wav
diff --git a/hindi_test_45s_16k.wav b/dev/hindi_test_45s_16k.wav
similarity index 100%
rename from hindi_test_45s_16k.wav
rename to dev/hindi_test_45s_16k.wav
diff --git a/hindi_test_60s_16k.wav b/dev/hindi_test_60s_16k.wav
similarity index 100%
rename from hindi_test_60s_16k.wav
rename to dev/hindi_test_60s_16k.wav
diff --git a/japanese_test_120s_16k.wav b/dev/japanese_test_120s_16k.wav
similarity index 100%
rename from japanese_test_120s_16k.wav
rename to dev/japanese_test_120s_16k.wav
diff --git a/japanese_test_15s_16k.wav b/dev/japanese_test_15s_16k.wav
similarity index 100%
rename from japanese_test_15s_16k.wav
rename to dev/japanese_test_15s_16k.wav
diff --git a/japanese_test_180s_16k.wav b/dev/japanese_test_180s_16k.wav
similarity index 100%
rename from japanese_test_180s_16k.wav
rename to dev/japanese_test_180s_16k.wav
diff --git a/japanese_test_240s_16k.wav b/dev/japanese_test_240s_16k.wav
similarity index 100%
rename from japanese_test_240s_16k.wav
rename to dev/japanese_test_240s_16k.wav
diff --git a/japanese_test_300s_16k.wav b/dev/japanese_test_300s_16k.wav
similarity index 100%
rename from japanese_test_300s_16k.wav
rename to dev/japanese_test_300s_16k.wav
diff --git a/japanese_test_30s_16k.wav b/dev/japanese_test_30s_16k.wav
similarity index 100%
rename from japanese_test_30s_16k.wav
rename to dev/japanese_test_30s_16k.wav
diff --git a/japanese_test_45s_16k.wav b/dev/japanese_test_45s_16k.wav
similarity index 100%
rename from japanese_test_45s_16k.wav
rename to dev/japanese_test_45s_16k.wav
diff --git a/japanese_test_5min_16k.wav b/dev/japanese_test_5min_16k.wav
similarity index 100%
rename from japanese_test_5min_16k.wav
rename to dev/japanese_test_5min_16k.wav
diff --git a/japanese_test_60s_16k.wav b/dev/japanese_test_60s_16k.wav
similarity index 100%
rename from japanese_test_60s_16k.wav
rename to dev/japanese_test_60s_16k.wav
diff --git a/mandarin_test_120s_16k.wav b/dev/mandarin_test_120s_16k.wav
similarity index 100%
rename from mandarin_test_120s_16k.wav
rename to dev/mandarin_test_120s_16k.wav
diff --git a/mandarin_test_15s_16k.wav b/dev/mandarin_test_15s_16k.wav
similarity index 100%
rename from mandarin_test_15s_16k.wav
rename to dev/mandarin_test_15s_16k.wav
diff --git a/mandarin_test_30s_16k.wav b/dev/mandarin_test_30s_16k.wav
similarity index 100%
rename from mandarin_test_30s_16k.wav
rename to dev/mandarin_test_30s_16k.wav
diff --git a/mandarin_test_45s_16k.wav b/dev/mandarin_test_45s_16k.wav
similarity index 100%
rename from mandarin_test_45s_16k.wav
rename to dev/mandarin_test_45s_16k.wav
diff --git a/mandarin_test_60s_16k.wav b/dev/mandarin_test_60s_16k.wav
similarity index 100%
rename from mandarin_test_60s_16k.wav
rename to dev/mandarin_test_60s_16k.wav
diff --git a/spanish_test_120s_16k.wav b/dev/spanish_test_120s_16k.wav
similarity index 100%
rename from spanish_test_120s_16k.wav
rename to dev/spanish_test_120s_16k.wav
diff --git a/spanish_test_15s_16k.wav b/dev/spanish_test_15s_16k.wav
similarity index 100%
rename from spanish_test_15s_16k.wav
rename to dev/spanish_test_15s_16k.wav
diff --git a/spanish_test_180s_16k.wav b/dev/spanish_test_180s_16k.wav
similarity index 100%
rename from spanish_test_180s_16k.wav
rename to dev/spanish_test_180s_16k.wav
diff --git a/spanish_test_240s_16k.wav b/dev/spanish_test_240s_16k.wav
similarity index 100%
rename from spanish_test_240s_16k.wav
rename to dev/spanish_test_240s_16k.wav
diff --git a/spanish_test_300s_16k.wav b/dev/spanish_test_300s_16k.wav
similarity index 100%
rename from spanish_test_300s_16k.wav
rename to dev/spanish_test_300s_16k.wav
diff --git a/spanish_test_30s_16k.wav b/dev/spanish_test_30s_16k.wav
similarity index 100%
rename from spanish_test_30s_16k.wav
rename to dev/spanish_test_30s_16k.wav
diff --git a/spanish_test_45s_16k.wav b/dev/spanish_test_45s_16k.wav
similarity index 100%
rename from spanish_test_45s_16k.wav
rename to dev/spanish_test_45s_16k.wav
diff --git a/spanish_test_60s_16k.wav b/dev/spanish_test_60s_16k.wav
similarity index 100%
rename from spanish_test_60s_16k.wav
rename to dev/spanish_test_60s_16k.wav
diff --git a/turkish2_test_120s_16k.wav b/dev/turkish2_test_120s_16k.wav
similarity index 100%
rename from turkish2_test_120s_16k.wav
rename to dev/turkish2_test_120s_16k.wav
diff --git a/turkish2_test_15s_16k.wav b/dev/turkish2_test_15s_16k.wav
similarity index 100%
rename from turkish2_test_15s_16k.wav
rename to dev/turkish2_test_15s_16k.wav
diff --git a/turkish2_test_180s_16k.wav b/dev/turkish2_test_180s_16k.wav
similarity index 100%
rename from turkish2_test_180s_16k.wav
rename to dev/turkish2_test_180s_16k.wav
diff --git a/turkish2_test_240s_16k.wav b/dev/turkish2_test_240s_16k.wav
similarity index 100%
rename from turkish2_test_240s_16k.wav
rename to dev/turkish2_test_240s_16k.wav
diff --git a/turkish2_test_300s_16k.wav b/dev/turkish2_test_300s_16k.wav
similarity index 100%
rename from turkish2_test_300s_16k.wav
rename to dev/turkish2_test_300s_16k.wav
diff --git a/turkish2_test_30s_16k.wav b/dev/turkish2_test_30s_16k.wav
similarity index 100%
rename from turkish2_test_30s_16k.wav
rename to dev/turkish2_test_30s_16k.wav
diff --git a/turkish2_test_45s_16k.wav b/dev/turkish2_test_45s_16k.wav
similarity index 100%
rename from turkish2_test_45s_16k.wav
rename to dev/turkish2_test_45s_16k.wav
diff --git a/turkish2_test_60s_16k.wav b/dev/turkish2_test_60s_16k.wav
similarity index 100%
rename from turkish2_test_60s_16k.wav
rename to dev/turkish2_test_60s_16k.wav
diff --git a/turkish_test_120s_16k.wav b/dev/turkish_test_120s_16k.wav
similarity index 100%
rename from turkish_test_120s_16k.wav
rename to dev/turkish_test_120s_16k.wav
diff --git a/turkish_test_15s_16k.wav b/dev/turkish_test_15s_16k.wav
similarity index 100%
rename from turkish_test_15s_16k.wav
rename to dev/turkish_test_15s_16k.wav
diff --git a/turkish_test_180s_16k.wav b/dev/turkish_test_180s_16k.wav
similarity index 100%
rename from turkish_test_180s_16k.wav
rename to dev/turkish_test_180s_16k.wav
diff --git a/turkish_test_240s_16k.wav b/dev/turkish_test_240s_16k.wav
similarity index 100%
rename from turkish_test_240s_16k.wav
rename to dev/turkish_test_240s_16k.wav
diff --git a/turkish_test_300s_16k.wav b/dev/turkish_test_300s_16k.wav
similarity index 100%
rename from turkish_test_300s_16k.wav
rename to dev/turkish_test_300s_16k.wav
diff --git a/turkish_test_30s_16k.wav b/dev/turkish_test_30s_16k.wav
similarity index 100%
rename from turkish_test_30s_16k.wav
rename to dev/turkish_test_30s_16k.wav
diff --git a/turkish_test_45s_16k.wav b/dev/turkish_test_45s_16k.wav
similarity index 100%
rename from turkish_test_45s_16k.wav
rename to dev/turkish_test_45s_16k.wav
diff --git a/turkish_test_60s_16k.wav b/dev/turkish_test_60s_16k.wav
similarity index 100%
rename from turkish_test_60s_16k.wav
rename to dev/turkish_test_60s_16k.wav
diff --git a/test/SOURCES.md b/test/SOURCES.md
new file mode 100644
index 0000000000000000000000000000000000000000..7289ea2e765ad422ba972dd5c9f0bd19ca5a3c5a
--- /dev/null
+++ b/test/SOURCES.md
@@ -0,0 +1,18 @@
+# test/ split — held-out clips (2026-07-11)
+
+Reserved for TESTING ONLY (dev/ is for validation and algo tuning).
+16 kHz mono s16 wav, cut from YouTube at the listed offset.
+
+| file | source | t | language (model-declared) |
+|---|---|---|---|
+| english3_test_{30,60}s_16k.wav | youtube.com/watch?v=PHL1j2ti420 | 9 s | English |
+| english4_test_{30,60}s_16k.wav | youtube.com/watch?v=PHL1j2ti420 | 193 s | English |
+| japanese2_test_30s_16k.wav | youtube.com/watch?v=fXV89VQ5dJQ | 0 s | Japanese |
+| arabic_test_{30,60}s_16k.wav | youtube.com/watch?v=Pfj4niPP0DY | 5406 s | Arabic |
+| french2_test_{30,60}s_16k.wav | youtube.com/watch?v=mAP-rkvoJ2A | 495 s | French |
+| turkish3_test_{30,60}s_16k.wav | youtube.com/watch?v=WvqFtpD7gOA | 1115 s | Turkish |
+| italian_test_{30,60}s_16k.wav | youtube.com/watch?v=zze5BdcvTp4 | 85 s | Italian |
+| turkish4_test_{30,60}s_16k.wav | youtube.com/watch?v=k3b3AffNofI | 697 s | Turkish |
+
+Numbering continues the whole-dataset count (dev/ has english..english2,
+turkish..turkish2, one each of french/hindi/japanese/mandarin/spanish).
diff --git a/test/arabic_test_30s_16k.wav b/test/arabic_test_30s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..347bd351f41da4e9ded7c125247fce88c8055e84
--- /dev/null
+++ b/test/arabic_test_30s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:89d125f51193e04b42fc4dbe7aff268533bdaece306379df3b6dd5a9ff2f2dbe
+size 960078
diff --git a/test/arabic_test_60s_16k.wav b/test/arabic_test_60s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..fa8f61317287390aa2396287cb205f60e9f4b8f3
--- /dev/null
+++ b/test/arabic_test_60s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:fc14c28499f4c16f102bf214d808f84ea9849b275733f3616c2c9e2383a79e1b
+size 1920078
diff --git a/test/english3_test_30s_16k.wav b/test/english3_test_30s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..777103487fe11e8d8146bc0783358f1807cb5851
--- /dev/null
+++ b/test/english3_test_30s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:7714bb89107227e58078e4a47e4f355d72f822092cd24319feaf3a311f27237c
+size 960078
diff --git a/test/english3_test_60s_16k.wav b/test/english3_test_60s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..188310221a6e61833c7dcde14e0f6fb5c0ec677a
--- /dev/null
+++ b/test/english3_test_60s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:5b9d08825e0c2168b561ec2b540a3529f01e8dc4963c8c4ca800a873d812f395
+size 1920078
diff --git a/test/english4_test_30s_16k.wav b/test/english4_test_30s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..86a7617346c8e1994ba20be8a98863eb33209d08
--- /dev/null
+++ b/test/english4_test_30s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:fde848ee0fab6f73388c724742b1d2dbaf79ac38e50cceebb15723b19660f398
+size 960078
diff --git a/test/english4_test_60s_16k.wav b/test/english4_test_60s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..4a6c010db7c1b9120c5593f355597626bd69e5aa
--- /dev/null
+++ b/test/english4_test_60s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:8a77c2219a286d6dbc5b9329267ea8b3109bd49a9efd6b1b0bedc1902f6730df
+size 1920078
diff --git a/test/french2_test_30s_16k.wav b/test/french2_test_30s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..4c01b126ca148eac61ba5ab82240a8cce3d49e49
--- /dev/null
+++ b/test/french2_test_30s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:b07abe89ef7cf16e54c4597b8c04c4ccd220c67640b112347bac7a30b023e3a5
+size 960078
diff --git a/test/french2_test_60s_16k.wav b/test/french2_test_60s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..c97200cd67e6971203e18797439367965b350c99
--- /dev/null
+++ b/test/french2_test_60s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:a51db8d7bd8caabbe1f12a775ae2f5218fef8157104cea9465e728c99f0abb12
+size 1920078
diff --git a/test/italian_test_30s_16k.wav b/test/italian_test_30s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..1405f554db28884ca9b2d5e38c4b6173f37f6630
--- /dev/null
+++ b/test/italian_test_30s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:9c936bc3c897934e864897d4662a94a5fc9a43b10f7bc058f16abcee1992049c
+size 960078
diff --git a/test/italian_test_60s_16k.wav b/test/italian_test_60s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..5c7d487681d3390b04dcb3fc212de06f7a50fd8a
--- /dev/null
+++ b/test/italian_test_60s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:05dceb9dd6645042828bd4a09dc82e4b0d9d6ac81dd3c42010418834dd03fa02
+size 1920078
diff --git a/test/japanese2_test_30s_16k.wav b/test/japanese2_test_30s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..970f90ed7ac2f8294fe7a0da170550823acd36d3
--- /dev/null
+++ b/test/japanese2_test_30s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:4621b64a99e74b4ba2dba2544588b2905b180881b898c4c8033079ad3b3fdc74
+size 960078
diff --git a/test/turkish3_test_30s_16k.wav b/test/turkish3_test_30s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..0954a045246a68192e9f7e337860096aa5031fb4
--- /dev/null
+++ b/test/turkish3_test_30s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:badb012c79028d3a1a3421ecff533f83e79476f73ad5d62fb4077cdc63a4a835
+size 960078
diff --git a/test/turkish3_test_60s_16k.wav b/test/turkish3_test_60s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..2ed5d462b8da1e94dad05931a27a64b75b995ade
--- /dev/null
+++ b/test/turkish3_test_60s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:0043e759c5709bc02f5eb1277cc90d2482336df9f21d8a35f871ad4e17dc49c2
+size 1920078
diff --git a/test/turkish4_test_30s_16k.wav b/test/turkish4_test_30s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..3f76b6f129869ce29c14d8501856b99b673475c2
--- /dev/null
+++ b/test/turkish4_test_30s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:273791668e6b7bf61e058d8eb883f33db1c9dfb455caecc2206d51d9099c289b
+size 960078
diff --git a/test/turkish4_test_60s_16k.wav b/test/turkish4_test_60s_16k.wav
new file mode 100644
index 0000000000000000000000000000000000000000..110ea55285b40297452524905a9408aaec5e16b4
--- /dev/null
+++ b/test/turkish4_test_60s_16k.wav
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:225ac2ba937df675006b3808ac429a4f8e76ca9ec94799c05fb114d741272436
+size 1920078