Correct spelling for the English word "fall upons" is [fˈɔːl əpˌɒnz], [fˈɔːl əpˌɒnz], [f_ˈɔː_l ə_p_ˌɒ_n_z] (IPA phonetic alphabet).
As per my knowledge, the phrase "fall upons" does not have a specific etymology. It appears to be a combination of the verb "fall" used with the preposition "upon", indicating an unexpected or sudden occurrence. However, please note that "fall upons" might be a less commonly used form or a regional variation of the phrase, so its etymology may not be widely recognized.