English is widely spoken and understood but, like everywhere, a little effort to know a few basic words never goes amiss. Note that 'please’ is not generally used in Icelandic. (The actual spelling of each phrase is followed by a phonetic spelling.)

Hello/good day Gó_an daginn (go-than dye-inn)
Good evening Gott kvöld (gott kvult)
Goodbye Bless
Yes Já (yow)
No Nei (ney)
Excuse me (to Afsakio get by someone) (af-sa-kith)
Excuse me (to apologise) Fyrirgefou (fee rir-gev-thoo)
Thank you Takk
Do you speak English? Talar pú ensku? (ta-lar thoo en-skoo)
May I have the bill, please? Má ég fá reikninginn? (Mow yeg fow rayk-nin-gin).
Cheers Skál (Scowl)