EI

This letter combination represents the sound /eɪ/.
It's most common in verbs.

E.g.
to convey -> ta conveie
to obey -> to obeie
to prey -> ta preie
to survey -> ta sôveie
to purvey -> ta pôveie

The letter combination represents /ɛr/ when it comes before r.
E.g.
to impair -> to empeire