In my hammered dulcimer band we play a tune called "Dulcimer Reel." The notes that the tune came on include a note that this tune is very difficult for fiddle players to play. We like to announce this at shows. Quite honestly, though, I have no idea - and I confess to having a feeling of not wanting to find out. (Our guitar player was going to have one of his fiddle-playing friends learn the tune.)
These sentences strike me very much the same way.
le x, le y, le z; le a; le 1, le 2.” (the x's, the y's, the z's; the a's; the ones, the twos.)
It's hard to know what the concern was here. Andrew speculated that it had to do with the words for X and Y in 1931 (and/or before the 1920's) but my hunch is that these expressions were contrived to demonstrate Ido's plural article "le". Since Esperanto doesn't have a plural article, we must do the "hard" task of tacking the plural on the end, along with a vowel to make it easier to pronounce. Ironically, the English translation does exactly that. "Ex" becomes "exes" or "x's" just as "Z" becomes "Z-oj".
“Il ja kontas bone, ma il ankore kalkulas male.” (He already counts (adds up) well, but he still calculates badly.)
Others have already demonstrated that it's possible to avoid the double meaning of Esperanto "kalkuli" (which means both to count and to do math). Quite frankly, I find this just silly. I remember being told that in Spanish you can't distinguish between "sky" and "heaven" because there's one word for both. Esperanto is the same way. Still, you can always make sure your meaning is clear the same way you do in any language - by carefully choosing your words.
“Ili sideskis avan eli, eli sideskis ante ili.” (They (male) sat in front of them (female), they (female) sat before them (male).)
Looks like this one is difficult to say in English too... or is it? (The guys sat in front of the ladies, but the ladies sat down first.) Some of the next few exploit the same double meaning.
“Vartez la treno, se vu volas lo, ma ne expektez la arivo di vua amiko; il ne venos.” (Wait for the train, if you want to, but do not expect the arrival of your friend; he will not come.)
Atendu la trajnon, sed ne atendu ke...
The word atendu is used twice but there is no double meaning.
“Forsan es posibla agar altre.” (Maybe is it possible to do otherwise (in another way).)
Povas esti ke ni povas...
Povas esti ke eblas...
Eble ni povas...
I know a bit about Ido, having been the voice of Helmut von Druhler, the angry Idist from Radio Verda, read at least three books in Ido, and spent countless hours either debating or collaborating with Idists online. In the end, it's like arguing about which runner-up team should have won the tournament. It may be fun to say that your language has tunes that are difficult to play on the fiddle, but the truth might be something different.