I am no Welsh speaker myself, but I have studied the language casually. And since there's no pronunciation listed, I'll try to describe it here: The Welsh "LL" sounds different from any letters (or diphtongs) we have in English. It's hard to explain (and if you're interested enough I recommend you to look up videos or audio files to hear it) but the usual instructions for producing the sound is to put your tongue in position to say a normal L, and then blowing/whistling. To elaborate a bit more on what it should sound like, imagine a combination between an L, an H and a hiss.Personally, while I've become decent at pronouncing it when followed by a vowel (like Llewelyn or Llanfair), I still find it difficult to make it sound natural when directly followed by a consonant (like in Mallt here), so don't be put off if it seems too difficult. To compare the pronunciation of Mallt with slightly more familiar sound/words, I'd imagine it would sound more similar to German (or to some extend Dutch) "Macht" than to English "Malt", just with slightly more hissing at the "ch" part. Coincidentally, German (and Dutch) "Macht" also translates to "Might" which happens to be the meaning of the first half of Mathilda, which Mallt appears to be derived from (according to this site).
The Welsh "LL" sounds different from any letters (or diphtongs) we have in English. It's hard to explain (and if you're interested enough I recommend you to look up videos or audio files to hear it) but the usual instructions for producing the sound is to put your tongue in position to say a normal L, and then blowing/whistling. To elaborate a bit more on what it should sound like, imagine a combination between an L, an H and a hiss.
Personally, while I've become decent at pronouncing it when followed by a vowel (like Llewelyn or Llanfair), I still find it difficult to make it sound natural when directly followed by a consonant (like in Mallt here), so don't be put off if it seems too difficult.
To compare the pronunciation of Mallt with slightly more familiar sound/words, I'd imagine it would sound more similar to German (or to some extend Dutch) "Macht" than to English "Malt", just with slightly more hissing at the "ch" part.
Coincidentally, German (and Dutch) "Macht" also translates to "Might" which happens to be the meaning of the first half of Mathilda, which Mallt appears to be derived from (according to this site).