"Bidh iad a' dèanamh uisge-beatha air a' Ghàidhealtachd."
Translation:They make whisky in the Highlands.
I would not say it is silent. It sounds like a /w/ to me. It is quite normal, in most European languages, with the notable exception of English (and possibly some of the languages like Welsh?) for /v/ and /w/ to be interchangeable according to language, dialect, broad/slender etc. In Gaelic it seems that each word with a mh/bh has its own rules for who pronounces it each way. Just accept either.
It is because English is an exception that you so often hear foreigners (from lots of different places) getting confused.