Where does “acostumada” come from?

acostumada (Occitan) comes from Occitan -ada, from Latin -ata, from Latin -atus, from Proto-Italic -ātos, from Proto-Indo-European -éh₂tos — Forms adjectives from nouns, indicating the possession of a thing or a quality.

Ancestry of “acostumada”, step by step

Step	Language	Word	Meaning
1	Occitan	-ada	-ing
2	Latin	-ata	nominative feminine singular of -ātus; nominative...
3	Latin	-atus	-ed, -ate, -like; Form of -tus appended to nouns
4	Proto-Italic	-ātos	—
5	Proto-Indo-European	-éh₂tos	Forms adjectives from nouns, indicating the possession of a thing or a quality

Every word from Proto-Indo-European -éh₂tos →