Names skill between Castle #2 and castle #3 can't hear difference between bochd and bhochd.
Just finished a followup practice on this skill. Had problems with 2 questions - one the "Morag bhochd" question (posted under sentences a few minutes ago) and the other to decide whether the speaker is saying the single word bochd or bhochd. In the question to identify whether a single word is lenited or not, I cannot hear any difference between the word on the recording, the answer "bochd" and the answer "bhochd". I realize fluent speakers might be able to hear a difference. But as a learner, I can hear no difference and I've had this question several times now and each time I'm just guessing.
It's the same sort of distinction as in the ‘G’ vs ‘Gh’ situation in your other post. One thing to remember is that although ‘Bh’ (and ‘Mh’) often make a ‘V’ sound, it's not always quite the English ‘V’ that is generally produced with the top teeth on the bottom lip, but can be more closely related to a loose ‘B’ or ‘M’, in that it's made with the top lip on the bottom lip (the same goes for the Gaelic ‘F’)—if you hold an ‘M’ sound (essentially humming), and then ever so slightly open your lips, you have this ‘V’ sound.
It's a minute difference, and it probably wouldn't cause any issues to just use the English ‘V’, but the reason I'm saying is to be aware of how it's perhaps even closer to a ‘B’ than an English ‘V’, making the distinction a little trickier, and also for the sake of practising it in order to aid distinction.
So again, when listening for the difference, try to hear the hard onset of a ‘B’ vs the smoothness of the ‘Bh’ that doesn't have such a solid stop/start in its enunciation.
I have this problem with lenited words often because I have issues with distinguishing consonants. I've found that I can get the answer right if I pay attention to the gender of the speaker (usually a man for one and a woman for the other). Then I can move on. In conversation you will only need to understand that bochd or bhochd was said, so you'll get the speaker's meaning. That's what really matters.