'W' is a vowel in Welsh. What's more, Welsh is a transparent language (as linguists call it). This means that each letter in the language's written form is associated with a single sound (more or less) in the spoken language. The Welsh 'w' is therefore always pronounced much like the English 'oo'.
Exceptions to Welsh orthographical transparency would be:
* the letter 'Y' can have one of two sounds: 'ee' or 'uh'. There are clear rules as to which to use. (In Turkish, this difference is indicated by the lack of a dot over the 'i' for the dark ('uh') sound. The clear sound uses the familiar 'i' with a dot).
* vowels can be either long or short, so an 'i' can either be short as 'i' in 'pig' or long like the 'ee' in 'seed'. Where there is any doubt, a circumflex can be put over the vowel to indicate that it is long, such as the 'w' in 'dŵr'.
Otherwise, you pretty much pronounce Welsh words as you see them. You need to know the rules, though. The Welsh alphabet has a number of digraphs (ch, dd, ff, ng, ll, ph, rh, th) that figure in the alphabet as single letters and are sorted as single letters in dictionaries and indices for example.
Other languages use letters that in English are consonants to indicate vowels or semi-vowels. An 'r' in Czech, for example, can be a vowel as in 'Brno'. The same applies to the Czech 'l' as in 'Vltava'.
English is unusual in that its orthography makes pretty much no sense at all unless you're a specialist in language history. So applying English orthographical conventions to other languages often says more about English than it does about the language being commented upon.
I notice that somebody else has already commented on the use of spaces between words, so I'll not repeat it here.