SpiRit-LM: Interleaved Spoken and Written Language Model

Tu Anh Nguyen, Benjamin Muller, Bokai Yu, Marta R. Costa-jussa, Maha Elbayad, Sravya Popuri, Christophe Ropers, Paul-Ambroise Duquenne, Robin Algayres, Ruslan Mavlyutov, Itai Gat, Mary Williamson, Gabriel Synnaeve, Juan Pino, Benoît Sagot, Emmanuel Dupoux


Abstract
We introduce SpiRit-LM, a foundation multimodal language model that freely mixes text and speech. Our model is based on a 7B pretrained text language model that we extend to the speech modality by continuously training it on text and speech units. Speech and text sequences are concatenated as a single stream of tokens, and trained with a word-level interleaving method using a small automatically curated speech-text parallel corpus. SpiRit-LM comes in two versions: a Base version that uses speech phonetic units (HuBERT) and an Expressive version that models expressivity using pitch and style units in addition to the phonetic units. For both versions, the text is encoded with subword BPE tokens. The resulting model displays both the semantic abilities of text models and the expressive abilities of speech models. Additionally, we demonstrate that SpiRit-LM can learn new tasks in a few-shot fashion across modalities (i.e., ASR, TTS, Speech Classification). We make available model weights and inference code.1,2
Anthology ID:
2025.tacl-1.2
Volume:
Transactions of the Association for Computational Linguistics, Volume 13
Month:
Year:
2025
Address:
Cambridge, MA
Venue:
TACL
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Publisher:
MIT Press
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Pages:
30–52
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URL:
https://aclanthology.org/2025.tacl-1.2/
DOI:
10.1162/tacl_a_00728
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Cite (ACL):
Tu Anh Nguyen, Benjamin Muller, Bokai Yu, Marta R. Costa-jussa, Maha Elbayad, Sravya Popuri, Christophe Ropers, Paul-Ambroise Duquenne, Robin Algayres, Ruslan Mavlyutov, Itai Gat, Mary Williamson, Gabriel Synnaeve, Juan Pino, Benoît Sagot, and Emmanuel Dupoux. 2025. SpiRit-LM: Interleaved Spoken and Written Language Model. Transactions of the Association for Computational Linguistics, 13:30–52.
Cite (Informal):
SpiRit-LM: Interleaved Spoken and Written Language Model (Nguyen et al., TACL 2025)
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PDF:
https://aclanthology.org/2025.tacl-1.2.pdf