"On another matter can anyone explain why we have nouns in declensions, and what makes them feminine or masculine? Are there neuters also?"
"Because grammarians like patterns! "
For declenion, let me try this explanation:
Delension is about division based on a scheme:
http://en.wikipedia.org/wiki/Declension decribes it as "is a paradigm of inflected nouns and adjectives". Paradigm is a good word as it could be seen as an organising principle.
One can surmise from this that grammarians look at a language and after analysis, pick out what divisions important and give them names. This is not done arbitrarily, put around a scheme.
Let's look at English, a language you are all familiar with. If we use the definition supplied above (by Wiki!) regarding noun and adjective inflexions, we can see English as modifying its nouns for number (singualr vs. plural) and ownership (apostophy s), ex: cat vs. cats or ox vs. oxen (number); cat vs. the cat's paw, or ox vs. the ox's strength.
Adjectives dont seem to modify in English (off the top of my head)
The above analysis could be termed a theme or paradigm, in the example of english, number and case. The case in English is the genitive case, used to show relationship and ownership.
So what of declensions? ONce we select a theme (number, for example) we can then could up all the different examples of how to create a plural in English. Some exmaples are: ox --> oxen; cat -->cats; fish --> fish; sky --> skies. If these come to 5 or 6 or 7 (or whatever number), they are the count of declensions.
So, Englsih has a handful of declensions in the theme of number/how to make a plural.
If the theme is case, English has the genitive (some might say a nominative too, but I prefer to see that as existing when one has a full case set. For all I know, many Englsih nominative case nouns were variously once old genetive, accusative, or dative or locative etc forms, like how in irish the masculine dative took over from the nominative, so made talk of the nominative more complex or just a mute point. Someone with more knowledge on anglo-Saxon could chip in here).-->
So if the genetive as theme = 1, we now count all the ways that the ownership relation is provided for in the language...cat --> cat's tail, 0xen -->oxen's feet, fish --> fishes scales, wine -->wine's flavour. So, we are left with 1 declension (+es in writing is another one, but it is really an orthogrpahic convention, by the looks of it). If anyone knows another declension, please point it out.
To summ up for English: 2 themes with at last 5, and 1 declension respectively for 'number' & 'case'.
IN Irish then, the 'nodal theme' that has given rise to declension has been the inflection into the genitive singular case. Grammarians have used this to cathegorise nouns, putting them into 5 declensions because Latin (or some classical form) had them.
The problem is that, based on the actual uasge, we get very much more. SOme dialects have collapsed the case system (much of Conemara), while others have kepts them better (Cork: Oilean Chleire). Some dialects use the old weak gen pl (like Mayo, as far as I can see), while others prefer the strong plural (Conemara). Munster seems to prefer the datives to take over from nominative, fearaibh for fir (dat pl --> nom sing [am I correct here?!], while Conemara allows the genetive to take over in many cases. Donegal can have a difference between long and short L and N (L/n & N/n), and this results in declensions of the genitive not seen in other places.
So, without doing out a list of the possibles decleions in Irish, let's try to see the themes: number, case, gender
Theme 1: (Number). Most nouns have sing and pl (except mass nouns like aimsir 'weather'). the lieks of aimsir are then a declension. others: cat -->cait, bus --> busanna, lamh -->lamha....maybe 20 forms???
Theme 2(case). Any inflexional language has a spectrum of inflecion, from most inflected to least. you might find old speakers in Munster with full nom, gen, dat and for both singualr and plural in some words, while others (like aimsir) have only a genitve form, or other (like bus) have only a plural form.
So...one might subdivide on a spectrum from full inflexion to just one inflexion. Other subdivisions are weak and strong plurals, or words which admit a mixture, or words which natives feel can go either way.
At this point we are at hundreds of potential declensions...
Theme 3 (gender). There are masculine, feminine, and words that swing both ways. So 3 might be the number here.
I am of the feeling that declension is actually one of those this that are slightly non-linear; easy to set up, hard to count and analyse in practice. I would seem, in my experience, that knowing how to take a word and mutate it based on its structure is a better way than memorising all the variables (not that been careful is not warranted -it can be easy to start inflexting bus as a M1 noun bus -->bhuis, mbus etc when it is M4 (as the dictionary goes), bus -->bus, busanna