I am Irish. So what we say is the word “CHEERS”. I as well get blocks with “TH” words. Also another thing we do is give the “thumbs up hand gesture”. When I was a teenager I have a sever stammer even up to this day (age 47), I purchased two books. A book on antonyms and a book on synonyms. At that time I was searching for words that I could easily say and would not block on. Did it help me? Not really. But the word “cheers” I have yet in my 47 plus years of life not blocked on that word. Good luck OP in your search.