The long OY sound, [ɔɪ̯], is typically spelled with an OI: oil, foil, voice; or with an OY: boy, enjoyed,destroy.
In some cases, it can be spelled OIS as in Illinois.
The long OY sound, [ɔɪ̯], is typically spelled with an OI: oil, foil, voice; or with an OY: boy, enjoyed,destroy.
In some cases, it can be spelled OIS as in Illinois.