Like non‐verbal communication, paralinguistic communication is rooted in anatomical and physiological factors. Paralinguistic form‐meaning relations arise from the way these affect speech production, with some fine‐tuning by the cultural and linguistic context. The effects have been classified as “biological codes,” following the terminological lead of John Ohala's Frequency Code. Intonational morphemes, though arguably non‐arbitrary in principle, are in fact heavily biased toward these paralinguistic meanings. Paralinguistic and linguistic meanings for four biological codes are illustrated. In addition to the Frequency Code, the Effort Code, and the Respiratory Code, the Sirenic Code is introduced here, which is based on the use of whispery phonation, widely seen as being responsible for the signaling and perception of feminine attractiveness and sometimes used to express interrogativity in language. In the context of the evolution of language, the relations between physiological conditions and the resulting paralinguistic and linguistic meanings will need to be clarified.