The most common and most likely answer to this crossword clue is the 8 letter word MUTTERED
I've seen this crossword clue in The Sunday Telegraph
M
U
T
T
E
R
E
D
More clues leading to the result MUTTERED
Buddy explains!
The straight part
We know that "produced speech hard to follow" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case produced speech hard to follow = muttered.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MUTTERED mean?
MUTTERED verb- To utter words, especially complaints or angry expressions, indistinctly or with a low voice and lips partly closed; to say under one's breath.
- To speak softly and incoherently, or with imperfect articulations.
- To make a sound with a low, rumbling noise.