Three Useful Phrases.

もう一度お願いします。　もういちどおねがいします。
Mou ichido onegaishimasu.
One more time, please.

ゆっくり話すお願いします。　ゆっくりはなすおねがいします。
Yukkuri hanasu onegaishimasu.
Please speak slowly.

ローマ字書いてをください。　ろまじかいてをください。
Romaji kaite wo kudasai.
Please write it down in Romaji.

もう - Mou = Again.
一度 - ichido = Once.
お願いします - Onegaishimasu = Please, to request a service, Please do something for me.
書いて - Kaite = Is the 'Te' form or conjugation of the verb 'Kaku' 書く.
ローマ - Roma.
字 - Ji.
ローマ字 - Romaji.

When you see the small 'tsu' っ it indicates, not only a double consonant but also a small pause.
So ゆっくり - Yu-kkuri.

Kanji Break Down:

一 = One, One radical (No. 1).
ON Reading: Ichi, Itsu.
KUN Reading: Hitotsu.

度 = Degrees, Occurrence, Time, Counter for occurrences.
On Reading: Do, To, Taku.
KUN Reading: Tabi, Tai.

願 = Petition, Request, Vow, Wish, Hope.
ON Reading: Gan.
KUN Reading: Negau, Negai

話 = Talk, Tale.
ON Reading: Wa.
KUN Reading: Hanasu, Hanashi.

字 = Character, Letter, Word.
ON Reading: Ji
KUN Reading: Aza, Azana.

書 = Write
ON Reading: Sho
KUN Reading: Kaku, Gaki.