The word 'sigao' (keep silent) in 1 Corinthians 14 consistently refers to limited, context-specific silence

The word 'sigao' can mean refraining from a particular kind of speech in a certain context (per Anthony Thiselton). In verse 28, it means stop speaking in tongues if there is no interpreter -- not total silence in all things. In verse 30, it means stop prophesying if someone else has a prophecy -- again, limited silence. The same pattern applies in verse 34: silence in regard to a specific kind of speech (judging prophecy), not total silence in all contexts.