it has two tone. One is first, the other is fourth tone. when you use first tone, it just like well, oh , you usually use. when you use fourth, I shouw you a dialog A: excuse me? B: Yes? Hey( 嘿（hei））= excuse me Hope can help u

嘿(hēi), but in fact people usually pronounce it like a fourth tone when they use 嘿 to attract sb's attention. 嗨, pinyin is hāi, or hēi, same meaning as 嘿, and actually we pronounce it like a fourth tone too. 喂(wèi), the most informal way to say hey in mandarin, and it's better for you to use it carefully. btw, people usually pronounce it as wéi on the phone.

Hey in Chinese could be "嗨"/“嘿”/“唉”，the same tone as it in English.

Hello theresa. 喂 [wèi] to attract attention as in "Hey you there" 嘿 [hēi] when showing feelings of surprise , interest or anger

HEY= 喂, first tone in Mardarin Chinese.