Purpose: This study investigates the articulatory strategies used by male and female speakers to produce vowel sounds.

Method: Secondary data analysis of a pre-existing articulatory corpus was carried out. Dynamic midsagittal ultrasound and acoustic data from 36 speakers of Northern English (21 females and 15 males) were analysed, representing 17 vowel phonemes in a controlled phonetic environment. Articulatory landmarks corresponding to the tongue root, dorsum and mandibular short tendon were automatically labelled in the ultrasound image, and their dynamic displacement was analysed using Generalised Additive Mixed Modelling. Dynamic formant trajectories for F1 and F2 were analysed using the same method.

Results: Significant articulatory differences were found between male and female speakers for several vowels. Increased tongue dorsum fronting and lowering was found for female GOOSE and GOAT vowels. Greater jaw opening was found in female TRAP, START, SQUARE, DRESS, MOUTH and LOT, accompanied by greater dorsal retraction, compared to male speakers. For STRUT / FOOT, there was greater retraction of the tongue dorsum in males. For some vowels, e.g. TRAP and DRESS, corresponding differences were detected in normalised formant trajectories, but the magnitude of the acoustic differences was typically very small, and in some cases, such as MOUTH and LOT, no differences in normalised F1 or F2 were detected, despite underlying articulatory differences.

Conclusions: Many of the differences we find point to increased jaw opening, and greater involvement of the jaw as an articulator in female speakers. This wider strategy affects the production of multiple vowels, but it only manifests acoustically in some cases, suggesting the involvement of generalisation mechanisms. Clinical implications for gender affirming speech therapy are discussed.