I think that none of them say how many words they teach you because acquiring vocabulary really isn't the most challenging part of learning any language. With Irish, getting a grasp of the grammar and syntax -- particularly the idioms unique to the language -- and developing a fluency in expressing yourself by using them correctly, is critically important. Acquiring vocabulary is secondary.
It would be hard for any program to tell you how many words it hopes to teach you in any case. For example, there are concepts that, in English, are expressed by using one word (the verb "laugh" for instance) that are expressed by two or more words in Irish (in this case, the verbal form of "laugh" is "déan gáire"...literally "make laughter"). So should they count that as one word or two? On the other hand, sometimes a single word can represent various concepts. For example, the one simple little word "a" can represent several words, depending on how it's used:
1) "O" (as in "O Lord hear us") when it's functioning as the vocative particle
2) The possessive adjectives 'his,' 'her' and 'their' (which it represents depends on how the word following it mutates)
3) It combines with the verbal noun to create an infinitive form, in which case it would probably be best translated as "to."
So, when you've learned "a," how many words do you know?
Irish verbs can also change meaning depending on the prepositions they're paired with. So, for example, "Éirigh" (rise) when paired with the preposition "le" becomes "succeed," and when paired with the preposition "as" becomes "retired." So, when such verbs can have three or more meanings, how many words have you learned when you've learned that verb?
The sheer volume of words you know at the end of a course doesn't really mean much. Vocabulary will naturally increase as your facility with the language increases...as you start using more complicated learning methods, as you start reading books and articles in the language, as you start talking to other people, etc.
What you should consider when looking at a learning program is:
1) How do you learn best? Most people do best using a combination of a computer module or CD learning method to help with pronunciation and conversation in conjunction with a book method to learn grammar and syntax.
2) What are your goals for learning the language? Do you hope to become fluent, or are you only looking to acquire some key words and phrases?
3) Do you lean toward a particular dialect? While it's true that most learners eventually acquire something of a mixed dialect (and the dialects are mutually intelligible), if you have a particular interest in one part of the country or another, you may not be happy to learn that you're learning Munster pronunciation when your emotional connection is with Donegal!
In any case, if you're going to be self-teaching, your best bet, after thinking these things through, would be to read through the reviews here:
http://www.learnirishgaelic.com/productcomparison/
And pick a couple of different types of methods that sound like they would best suit your learning style. Or pick one to start (generally a good approach is to pick a book method with an audio CD first, then go to a computer program once you've begun to get a grasp on the basic structures), with the understanding that you're probably going to eventually want more.
You'll also need a good dictionary, and we review most of them here:
http://www.learnirishgaelic.com/product ... tionaries/
I do, however, caution you against trying to use a dictionary to translate anything until you've really got a handle on how the language works. Irish syntax is so different from non-Celtic languages that straight dictionary translations inevitably lead to disaster!
Redwolf