Colin Raffel
Whether a single language model can do all NLP tasks at once when they're all framed as text-in-text-out — and whether that unification holds across languages.
T5 (Text-to-Text Transfer Transformer, 2020, lead author) made a methodological argument that the field had been resisting: every NLP task can be framed as the same kind of problem — give the model a string, ask for a string — and a single model trained on that framing handles them all. The follow-up T0 paper (2021) extended the argument to zero-shot multilingual generalization, showing that the same approach scales across languages with only modest performance loss. The combined line is the methodological precursor to almost every instruction-tuned multilingual LLM shipped since, including the ones ai100 currently evaluates.