It occurred to me to look up its etymology:
expatiate

SYLLABICATION: ex·pa·ti·ate
PRONUNCIATION: k-spsh-t
INTRANSITIVE VERB: Inflected forms: ex·pa·ti·at·ed, ex·pa·ti·at·ing, ex·pa·ti·ates
1. To speak or write at length: expatiated on the subject until everyone was bored. 2. To wander freely.
ETYMOLOGY: Latin expatir, expatit- : ex-, ex- + spatir, to spread (from spatium, space).
OTHER FORMS: ex·pati·ation —NOUN

An now I can guess etymology of "spatula", and "spatulate" (as in "spatulate fingertips".