Aci

It is composed of two syllables: "A" and "Ci".

Spelling	a
Closest English pronunciation	/ɑ:/
Hint	As the a in English "art".
Chinese Pinyin	ā á ǎ à
Common characters in names	阿

Spelling	ci
Closest English pronunciation	/ts-/
Hint	The /ts/ sound in "hats" but is voiced (vocal cord vibrates). Not /si:/ as in English letter "C".
Chinese Pinyin	cī cí cǐ cì
Common characters in names	慈 赐 辞 词 次