host: volume option; docs: voice adjustments beyond speed (volume, Flextalk profile)

README.md

@@ -46,7 +46,8 @@ Manual steps, if needed:
     setup/run.sh -v Sam -t "Hello." -o sam.wav
     setup/run.sh -v "Keith Bell" -t "Hello." -o keith.wav -p 100 -s 150
 
-Options: `-v` voice, `-t` text, `-o` output WAV, `-p` pitch, `-s` speed.
+Options: `-v` voice, `-t` text, `-o` output WAV, `-p` pitch, `-s` speed, `-V` volume
+(volume is engine-specific; not used by the Veskslop wrapper).
 
 ## Veskslop integration
 

docs/NOTES.md

@@ -82,6 +82,12 @@ final file `WatsonUNInstall.dll` is incomplete).
   Verified with the corrected DWORD registry: Kerry 0 st = 209 Hz, -6 st = 148 Hz,
   +6 st = 250 Hz (clamped at max); Keith 0 st = 119 Hz, +6 st = 170 Hz.
 - The wrapper maps semitones as `natural * 2^(st/12)` and clamps to the range.
+- volume: available through `ITTSAttributes` (host flag `-V`). Flextalk is linear
+  (0-65535, default 65535; half is about -6 dB). MSTTS is non-linear (0 = silence,
+  4096 about -24 dB, 65535+ full scale); treat it as on/off.
+- Flextalk per-speaker profile values are applied at voice load; `Expression` was
+  verified audible (0/59/100 produce different waveforms at equal duration). Changing
+  them requires a registry edit and re-selecting the voice.
 
 ## Decompiled corpora (Ghidra)
 

docs/TTS-DESIGN.md

@@ -260,10 +260,36 @@ record what the engine needs to interpret, add, or hide._
 ### Text handling
 
 - SAPI4 is ANSI/CP1252. The wrapper converts UTF-8 to CP1252 and maps emoji and
-  unmappable characters to spaces. Engine tag parsing is disabled, so input stays plain
+  unmappable characters to spaces. The host passes `TTSDATAFLAG_TAGGED`, so SAPI4 control
-  text (no SSML), matching the contract.
+  tags in the text are enabled at the engine level; tagged input is not part of this
+  contract and is untested. Plain text (no SSML) is the contract.
 - Lines up to 1000 characters are well within engine limits.
 
+### Other voice adjustments (beyond speed)
+
+All voices implement SAPI4 `ITTSAttributes`, so **pitch, speed and volume** exist at the
+API level. The Veskslop contract exposes only speed and pitch; volume is available in the
+host as `sapi4host -V <value>` and is not sent by Veskslop.
+
+- **Volume** (measured 2026-09-15):
+  - Flextalk: linear, range 0-65535, default 65535; half (32767) is about -6 dB, 0 is
+    silence.
+  - MSTTS: default is 0xFFFFFFFF; 0 is silence, but the response is not linear (for
+    example 4096 gives about -24 dB while 65535 and larger are full scale). Treat volume
+    as effectively on/off for MSTTS.
+- **Flextalk per-speaker profile** (applied at voice load, not runtime-adjustable):
+  values live in `HKLM\Software\AT&T\Watson\2.0\FlexTalk\2.0\Speakers\{GUID}` (see
+  `docs/NOTES.md` for the full list and defaults). `Pitch`/`Speaking Rate` set the natural
+  voice; **Expression** was verified to change the synthesis audibly (Keith Bell at
+  Expression 0 / 59 / 100 yields different waveforms with the same duration). Changing a
+  profile requires a registry edit and re-selecting the voice.
+- **MSTTS voice character** is fixed by the `.vce`/`.cfg` data; the engine exposes no
+  per-voice profile in the registry. Its effect variants (telephone, in Hall, in Stadium,
+  in Space) are separate voice modes with separate data, exposed as distinct voice IDs
+  (`mike-telephone`, `mary-hall`, ...), not runtime effects.
+- Not exposed by this integration: SSML, prosody/style tags, or SAPI4 attribute
+  extensions beyond pitch/speed/volume.
+
 ### Transport and latency
 
 - Installation is one command: `setup/install.sh` (system dependencies with sudo, wine

host/sapi4host.c

@@ -157,7 +157,7 @@ static void usage(void)
     fprintf(stderr,
             "usage: sapi4host -l\n"
             "       sapi4host -v <voice> -t <text> -o <out.wav>"
-            " [-p pitch] [-s speed]\n");
+            " [-p pitch] [-s speed] [-V volume]\n");
 }
 
 /* ------------------------------------------------------------------ */
@@ -168,6 +168,7 @@ int main(int argc, char **argv)
 {
     const char *voice = NULL, *text = NULL, *out = NULL;
     int pitch = -1, speed = -1;
+    long volume = -1;
     int i;
     TTSMODEINFO mode;
 
@@ -182,6 +183,7 @@ int main(int argc, char **argv)
         else if (!strcmp(argv[i], "-o")) out = argv[++i];
         else if (!strcmp(argv[i], "-p")) pitch = atoi(argv[++i]);
         else if (!strcmp(argv[i], "-s")) speed = atoi(argv[++i]);
+        else if (!strcmp(argv[i], "-V")) volume = strtol(argv[++i], NULL, 0);
         else { usage(); return 2; }
     }
     if (!voice || !text || !out) { usage(); return 2; }
@@ -257,9 +259,9 @@ int main(int argc, char **argv)
         return 1;
     }
 
-    /* Pitch and speed are optional: when unset, leave the engine's own
+    /* Pitch, speed and volume are optional: when unset, leave the engine's own
        voice profile untouched (probing/setting would override it). */
-    if (pitch >= 0 || speed >= 0) {
+    if (pitch >= 0 || speed >= 0 || volume >= 0) {
         WORD pmin = 0, pmax = 0;
         DWORD smin = 0, smax = 0;
 
@@ -284,6 +286,13 @@ int main(int argc, char **argv)
             printf("speed: %d (%lu..%lu)\n",
                    speed, (unsigned long)smin, (unsigned long)smax);
         }
+        if (volume >= 0) {
+            DWORD vdef = 0;
+            attr->lpVtbl->VolumeGet(attr, &vdef);
+            attr->lpVtbl->VolumeSet(attr, (DWORD)volume);
+            printf("volume: %ld (default %lu)\n",
+                   volume, (unsigned long)vdef);
+        }
     }
 
     {