Was hard to understand, in a way

Was hard to understand, in a way - SLURRED
Was hard to understand, in a way

It seems like the best approach would be to use the tag to emphasize the terms that refer to the difficulty of understanding spoken words, while using the or tags to simply differentiate the terms from one another. So, the tags might be arranged as follows:

Difficult to make out clearly
Indistinctly articulated
Unclear in pronunciation
Mumbled
Garbled
Hard to decipher

SLURRED