Pushing SFL out of its comfort zone: The role of SPCA structure in English and Spanish

•English Mood uses SPCA structure; Spanish Mood uses morphology and intonation.•SPCA structure is not intrinsically interpersonal.•SPCA structure can be used to express modal as well as other meanings.•SPCA structure can be seen as a syntactic-logical resource.•Syntax (realized by SPCA structure) is a tactic resource for clause construal.