If one has hiccups, and needs to make a beracha, is it a problem?
There are high chances that some words will be split and mispronounced...
Halachipedia has the laws of Birkat Hamazon. Hiccups are not mentioned but the following seems relevant:
Someone who is drunk
I deduce that if you would not speak before a king with hiccups like that, it is better (in this case) to wait till the hiccups go (assuming it is within the time to still say Birkat HaMazon – see the relevant halochos). But one may still say Birkat HaMazon. Of course CYLOR.
Moses had a speech impediment. If God had a problem with involuntarily split and mispronounced words, he would have picked another prophet.
If you are completely unintelligible, it may be a problem for others to answer amen if they can't actually hear the words.