Looks like I can search for " T S " to find the "ts sound that's not at the end"
% grep " T S " cmudict-0.7b | wc -l
991
Some of the non-proper nouns include ACCOUNTANCY, ANTSY, and ARTSY. I'll assume this is too close to the end to count, so require two sounds after the " T S ":
% grep -E " T S [A-Z0-9]+ [A-Z0-9]+" cmudict-0.7b | wc -l
853
(It doesn't have "spritzer" in the list, and uses the spelling "matzoh" instead of "matzo". I didn't look for a more complete list of word pronunciations.)
Finally, two words with two occurrences of the "ts" sound, neither at the end:
% grep -E " T S .*T S " cmudict-0.7b
ITSY-BITSY IH2 T S IY0 B IH1 T S IY0
TSETSE T S IY1 T S IY0
You're right. Though https://en.wikipedia.org/wiki/Boatswain says "formerly and dialectally also /ˈboʊtsweɪn/ BOHT-swayn", the dictionaries I checked do not list that alternative.
> Phonetic spelling bo'sun/bosun is attested from 1840. Fowler [1926] writes, "The nautical pronunciation (bō'sn) has become so general that to avoid it is more affected than to use it."
"Zeitgeist" seems like a bug, I've never heard anyone pronounce the leading 'z' as 'ˈts' in English, and doing so as a non-German might even be seen as 'over-pronuciation'.
(It doesn't have "spritzer" in the list, and uses the spelling "matzoh" instead of "matzo". I didn't look for a more complete list of word pronunciations.)
Finally, two words with two occurrences of the "ts" sound, neither at the end: