Correct spelling for the English word "Slaie" is [slˈe͡ɪə], [slˈeɪə], [s_l_ˈeɪ_ə] (IPA phonetic alphabet).
The word "sleigh" has its origin in Middle Dutch and Middle Low German. It is derived from the word "sleeden" in Middle Dutch, which means "to glide". This Middle Dutch word is also closely related to the Middle Low German word "sleden" with the same meaning. Over time, the word evolved into "sleigh" as we know it today in English.