The pronunciation is the same, so no, you cannot differentiate it from there. Context is the key in this case, and in many other cases.
The fact is that Japanese is a language with only a few sounds at its disposal, so homophones are to be expected. This is especially true considering that Japanese works with syllables, while other languages work with single letters, and this allows more combinations, because consonants are not necessarily attached to vowels: Japanese cannot have consonant clusters.
Things like br, pr, etc, are achieved by using the う (U) vowel, which is half-muted, and it makes the syllables look (and above all, sound) like consonant clusters.
I don't know about the etymology since I cannot understand Japanese well and I don't think I could check an Etymology dictionary... Unless there are in English.