The "slow tortoise" is only available in languages that use synthesised speech, not with real recorded speech by actual people as used in the Gaelic tree. I've noticed that sometimes speakers pronounce what sounds like an extra syllable compared to what we see written. Maybe changing the mouth from the "a" to the "sn" sounds does it? I mean, "A bheil i sneachd ann" doesn't make any sense. The verb can't have two subjects, and a native speaker wouln't do that.
One of my Gaelic teachers says that speakers add vowels and drop them often when actually speaking. He said that if "pumpkin" were a Gaelic word, it would be spoken as "pumpakin". It's just the nature of the language, and that's why it's so important to hear it spoken as often as you can. Take advantage of the sites that offer spoken language stories, etc. It really helps one get the rhythm and flow of the language.
At first i thought she said "a bheil i sneachd" as well. But then when I tried to say it, no matter how slow or fast I say it, it sounds like there is an "i" there. I think it is just a product of saying "bheil" followed by "sneachd." Try saying it out loud yourself. It's like the tail end of "bheiL" followed by "Sneachd" is just difficult to say so it comes out sounding like there is an "i" in there? What do y'all think?
Ann means "In existence", so "A bheil an t-uisge ann" means "Is there rain in existence", but that's not what we say in English. We never say "There is rain" we just say "It's raining". They really mean the same thing, but the lesson is giving a less literal translation of the phrase. So "A bheil sneachd ann?" = "Is there snow?" and "A bheil an t-uisge ann?" = "Is there rain?" / "Is it raining?"
That got me (non-native English) thinking. With snow, there is a difference between "it is snowing" and "there is snow", as snow persists - there can be snow without it snowing now. With rain there isn't - if it stopped raining, it may be wet, but there is then no "rain" (but maybe "rainwater"). Is that distinction possible in Gaelic, ie. distinguishing the process of snowing from the state of there being snow?
I hear the "extra" sound too and after much thought I am wondering if the "i" sound is actually coming from the l in bheil just as Alba is Al-a-ba / Al-i-ba depending on dialect??? I can't see a way to return to the recording now that time has passed, so perhaps someone currently on that lesson can listen again and see if that's the case?