The issue of doing recognition with several individual words that are only a syllable long and all rhyme with each other is not a satisfactorily-solved issue in speech recognition. This is another variation of the general issue of recognition of the English alphabet, which you can read people trying to find fixes for in every speech-recognition-related resource, unfortunately. There is no contextual cue for which one is the “real one” in the case you’re describing so as soon as there is any distance from the mic, the sounds are going to get mixed up.
The strategy for dealing with it is going to be some combination of removing confusing words from the model and fusing multiple words together that you know will be spoken together.
An example is that you don’t need the loose letter “U” if its presence there is just in order to let “U.S.” be recognized. In that case, make the word “U.S.”:
U.S. Y UW AH S
This will also improve the accuracy of words that are spoken near utterances of “U.S.”.
The next issue I see is that the “Q1” etc segment has a couple of obscure words before and after it, which suggests to me that this is a big language model. Do you have the opportunity to switch between smaller, more contextually-specific language models?
Can you do counting in either its own language model that you switch to, or with some kind of prefix? e.g. “Category 2” instead of just “2”.
The last thing is that you haven’t shown the entry in the language model or the pocketsphinx logging output, so I don’t know for sure whether your alteration is actually in your language model as far as pocketsphinx is concerned. If you remove “U” and “2”, are you able to recognize “Q1”? If not, there might be an issue in the language model in general.
In case you have confirmed that the language model is OK, and none of these approaches are options for you (although they are almost always options for an app that you can make design decisions about), the last possibility is to do it as a JSGF ruleset rather than a statistical ARPA model. Searching this forum for JSGF should help you get started.