• The elative case (elatiivi), denoting ‘internal location + from’; e.g. talosta ‘out of a house’.
• The illative case (illatiivi), denoting ‘internal location + to’; e.g. taloon ‘into a house’.
Now, let me understand something (and correct me if I’m wrong)… Even though they mean basically the opposite of each other, their names are pronounced the same in English (/ɪˈleɪtɪv/) 🙃
My source was Wiktionary, which lists both illative and elative as /ɪˈleɪtɪv/ in UK pronunciation. Perhaps there’s dialectal variation within the UK with this regard. The Wiktionarian who added the pronunciation information for both is I'm so meta even this acronym, who is a native speaker of Welsh and English (see here and here).