So may I ask, what do sheep and cows say in your language or other languages that are known to you? Or are there any other interesting animal sounds (e.g. cat sounds; 'faire ronron' for 'purr' in French is very nice)?
One interesting fact that I do know is that sheep said βη βη (sorry, can't do the accents on this computer) in ancient Greek [the first letter being the equivalent of a b and the second of a long e]; and this is useful in teaching beginners how to pronounce the relevant vowel (eta), since it is actually much closer to proper sheep sound than the corresponding vowel sound in 'baa'!