How many letters does the top answer for “introduce one's writing or speech with certain expressions” have?

The most common answer is interlard (9 letters).

Crossword clue: introduce one's writing or speech with certain expressions

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

interlard 9 letters wn-def

introduce one's writing or speech with certain expressions

intersperse 11 letters wn-def

introduce one's writing or speech with certain expressions