diff --git a/src/python/larynx_train/preprocess.py b/src/python/larynx_train/preprocess.py
index 9257367..1f6fa79 100644
--- a/src/python/larynx_train/preprocess.py
+++ b/src/python/larynx_train/preprocess.py
@@ -45,11 +45,18 @@ def main() -> None:
     parser.add_argument(
         "--single-speaker", action="store_true", help="Force single speaker dataset"
     )
+    parser.add_argument(
+        "--speaker-id", type=int, help="Add speaker id to single speaker dataset"
+    )
     parser.add_argument(
         "--debug", action="store_true", help="Print DEBUG messages to the console"
     )
     args = parser.parse_args()
 
+    if args.single_speaker and (args.speaker_id is not None):
+        _LOGGER.fatal("--single-speaker and --speaker-id cannot both be provided")
+        return
+
     level = logging.DEBUG if args.debug else logging.INFO
     logging.basicConfig(level=level)
     logging.getLogger().setLevel(level)
@@ -78,7 +85,7 @@ def main() -> None:
     _LOGGER.debug("Counting number of speakers/utterances in the dataset")
     speaker_counts: Counter[str] = Counter()
     num_utterances = 0
-    for utt in make_dataset(args.input_dir, args.single_speaker):
+    for utt in make_dataset(args.input_dir, args.single_speaker, args.speaker_id):
         speaker = utt.speaker or ""
         speaker_counts[speaker] += 1
         num_utterances += 1
@@ -146,7 +153,8 @@ def main() -> None:
     )
     with open(args.output_dir / "dataset.jsonl", "w", encoding="utf-8") as dataset_file:
         for utt_batch in batched(
-            make_dataset(args.input_dir, args.single_speaker), batch_size
+            make_dataset(args.input_dir, args.single_speaker, args.speaker_id),
+            batch_size,
         ):
             queue_in.put(utt_batch)
 
@@ -231,7 +239,9 @@ class PathEncoder(json.JSONEncoder):
         return super().default(o)
 
 
-def ljspeech_dataset(dataset_dir: Path, is_single_speaker: bool) -> Iterable[Utterance]:
+def ljspeech_dataset(
+    dataset_dir: Path, is_single_speaker: bool, speaker_id: Optional[int] = None
+) -> Iterable[Utterance]:
     # filename|speaker|text
     # speaker is optional
     metadata_path = dataset_dir / "metadata.csv"
@@ -271,15 +281,19 @@ def ljspeech_dataset(dataset_dir: Path, is_single_speaker: bool) -> Iterable[Utt
                 _LOGGER.warning("Missing %s", filename)
                 continue
 
-            yield Utterance(text=text, audio_path=wav_path, speaker=speaker)
+            yield Utterance(
+                text=text, audio_path=wav_path, speaker=speaker, speaker_id=speaker_id
+            )
 
 
-def mycroft_dataset(dataset_dir: Path, is_single_speaker: bool) -> Iterable[Utterance]:
+def mycroft_dataset(
+    dataset_dir: Path, is_single_speaker: bool, speaker_id: Optional[int] = None
+) -> Iterable[Utterance]:
     for info_path in dataset_dir.glob("*.info"):
         wav_path = info_path.with_suffix(".wav")
         if wav_path.exists():
             text = info_path.read_text(encoding="utf-8").strip()
-            yield Utterance(text=text, audio_path=wav_path)
+            yield Utterance(text=text, audio_path=wav_path, speaker_id=speaker_id)
 
 
 # -----------------------------------------------------------------------------