"A bheil èisg a' leum?"
Translation:Are fish jumping?
I've had a careful listen to the recordings of each word. Yes I agree they could be confused if you are not familiar with the slender ch. Both the sg and the ch have quite a lot of regional variation, which makes things more confusing. It is just a question of getting used to the sounds, but it may help to try to analyse them.
The ch in these recordings does have quite a lot of sibilant quality, compared to some other dialects – that is, it is verging towards an s or sh sound, but the sg is quite distinctive if you listen out for the two sounds. It is a clear sh, followed by a k sound.
In principle you can also distinguish the vowel length, (as the è indicates a long vowel, but English speakers are simply so bad at this distinction that I don't think that many people will find that helpful.
Rest assured that it will become easier with practice.
And of course, in these artificial sentences, you have the problem that both eich and èisg jump. It is difficult to imagine a situation in real life where you weren't sure which were jumping.