According to Naver & wiktionary, 말하다 is pronounced like [말:다]
Must I say it like 1. [마라다] 2. or with a ㄹㄹ sound [말라다] 3. or with a ㄹㄹ sound [말ㄹ하다]
A word with ㄹ+ㅎ sequence is pronounced with ㄹ as a tap (as in 마라, not 말라) together ㅎ.
I hope someone with a better knowledge could chime in, but in my experience, ㄹ and ㅎ are basically "pronounced together", which is possible because they are articulated in two different places. You tap the tip of your tongue and at the same time make the ㅎ sound with your throat.
In fact, in a normal speech, ㅎ in such a position usually just disappears altogether, so 말하다 would sound the same as 마라다.