Pronunciation: [bɪtwˈiːənbɹˌe͡ɪn] (IPA)
Correct spelling for the English word "betweeenbrain" is [bɪtwˈiːənbɹˌe͡ɪn], [bɪtwˈiːənbɹˌeɪn], [b_ɪ_t_w_ˈiː__ə_n_b_ɹ_ˌeɪ_n] (IPA phonetic alphabet).