"Good morning and good afternoon."
Translation:Madainn mhath agus feasgar math.
There are various rules about when lenition does (or doesn't) happen, but this is one of the rules. Words beginning with a vowel, l, n or r do not lenite. You may have seen in this lesson when people are being talked to there is sometimes an 'a' put before their name. This is known as the vocative, and is the form of the word when the person is being talked to rather than talked about. When possible this also causes lenition, but the a is there unless the name following it begins with a vowel sound (which lenition sometimes does).
L/N/R in fact can lenite, it's just not reflected in writing.
It would be really nice to have some explanation of why certain nouns get lenition where others don't in the course of the lesson. Lacking it will limit a would-be speaker from ever really achieving fluency - or even passing conversationality outside the scope of these phrases.
I agree it would be helpful. It's something useful that Mango does.
The thing with lenition is that it happens in a huge number of cases, for a variety of reasons, so you kind of have to learn the rules as you learn about the different cases.
A few rules of thumb we've come across so far: The Vocative case lenites names. The definite article lenites feminine nouns beginning with b, c, g, m, p. Adjectives that can be lenited are lenited when they apply to feminine nouns.
Later, when we get to the past tense, a lot of regular verbs are lenited to put them in the past tense.