Why lenition and eclipses?
What is the purpose of leniting a word? As I am learning a new language, my scientific side tries to make sense of why a language has a certain construct. What purpose does lenition and eclipses serve? It seems to complicate the language, rather than make it clearer.
At least as far as I've heard, and I'm not the resident Irish expert, they more or less developed out of laziness in pronunciation. However, that laziness was paired with much more specific, and also fairly different, articles, so that there was one for each gender and each case (IIRC Irish, if you go far enough back, had three genders and quite a few cases, unlike today). Eventually, rather than being based on pronunciation, eclipsis and lenition were codified in the grammar, and remained even after the articles all simplified to an or na. Because it is no longer tied to any obvious logic, there is some variation as to which one is used where in different dialects.
> Because it is no longer tied to any obvious logic, there is some variation as to which one is used where in different dialects.
I'm assuming you're talking about how one dialect lenites the dative while another eclipses it? If so, it's not because there's no underlying logic. When the dative case and accusative case merged, the southern dialects merged it with one case, which eclipsed, while the northern dialects merged it to the one that lenited. There is logic behind why it is the way it is.
I would argue that that logic isn't obvious logic, though, since you wouldn't know that just from looking at modern Irish. I meant more that if lenition and eclipsis had not developed in the past, and if they started developing now, they probably wouldn't look much like what we have. An can be followed by none or either, after all, so it clearly doesn't have much to do with ease of pronunciation today.
Based on the link above, it described lenition/eclipses as being a result of smoothing out the speaking of the language, so that it would flow from breath to breath. This makes sense. If one is naturally speaking a language, a fluent speaker, words tend to flow without pauses. The ends and beginnings change in sound. Knowing that helps, but as I am still an Irish n00b, remembering the rules are still slow to come.
But the smoothing out was based on an older form of the language. In modern Irish, you can have an bhean or an mbean, for instance, and neither seems any easier to say to me. If it was still really about smoothing out the language, and not grammar, then logically an would trigger the same process consistently. A place where the smoothing out is still more apparent would be something like mo + lenition, I feel. Mo mháthair is easier to say than mo máthair, for instance.