I am probably just spacing this section in the rules, but here goes.
Assume a person has equal facility with two languages (say, Classical Greek & Latin). How does one go about actually translating a book from one language to the other? Would you simply use the base rules for writing a book? Would this be like breaking a code?
How would you handle this?
Art & Adacame has rules for translating. Basically, need score of 5 in both languages, Artes Liberales of 2 (to represent literacy in both languages).
Such a translation has a reduction in Quality of 1.
Do the rules really require Artes Liberales 2? If both languages use the same alphabet, I thought you only need Artes Liberales 1 to read and write them both. (Maybe both statements are true nonetheless....)
That's right. However I never really understood that rationale. To me if you can't read it how could you write it?
It's a weird inconsistency in the general breadth of skills. Artes Liberales gives you seven arts and sciences, literacy, and foreign alphabets all in the mix. A language skill which costs the very same amount of XP really should also include the ability to read and write, if you're generally literate, and the use of the appropriate alphabet.
The alphabet thing always irks me. As someone who speaks some Russian and studied some Greek, I can attest that you master the alphabets almost in your spare time long before you ever reach a 1 in the language itself.
The mechanics reason AL is necessary for Literacy is that "[g]rammer concers theoritical questions of the strucutre of languages." I'm perfectly comfortable with one ability rather than 7 or more. In order for a character to write in two languages, they have to have spent at a minmum of 90 xp. 75 xp for one language, 15 xp for Artes Liberales, and they can write in their native tongue and the alternate language. To do any serious scholarly translation, they have to have spent 175 xps because the knowledge is written in Greek, Latin, Arabic or possibly Hebrew. To preserve the quality 225 xps to get to Language 6 in both languages. That's a fairly significant XP sink. We certainly don't need more, and I'd hate to see odd things splitting Artes Liberales apart would create, such as an expert on astrology not knowing about arithmetic or geometry.
As far as your specific experience with the alphabet, sure, and I think Artes Liberales models that. If you know the language and are literate in it, you know the alphabet. My contention is with the rule that an Artes Liberales of 1 allows one to write in two languages, so long as they share the same alphabet. That flies in the face of being able to understand the changes in grammar from one language to the next. Knowing a bit of German, I can say that even though they share the same alphabet, being able to write it is much harder than it is to read it. My Artes Libarles is too low. 
Something that is absolutely not covered by the system is orthography, declension and anything unknown to the illiterate. If it was, you'd have your reason why it costs so much.
I'm not arguing we should split Artes Liberales, I'm going the other way and arguing that skills like Languages are too narrow in comparison. I would suggest that if you have enough AL to read one language, you're literate in every language you speak and can use the appropriate alphabet. The literacy would come included in the Language skill, the way the astrology comes included in AL.
Whereas I would suggest that your German is too low and your AL is just fine. 
After all, you need one point higher to read than to write under the Ars system.
Certainly that's the way I feel about myself and my languages!
This allows me to differentiate between a true scholar and the diletante magus, though!
Huh, what'd I miss?
I thought you needed Language (eg. Latin) 4+ to read (based on ArM5 p. 32), but Language (eg. Latin) 5+ to write (ArM5 p.165)?
You certainly do. I wrote precisely the reverse of what I meant. My bad.
I wonder if that's what an Artes Liberales botch looks like.
Did you learn your Russian and Greek solely from speaking those languages or did you learn them from studying texts? (Most likely, of course, you did both).
In Ars, learning a language appears to be based on simply speaking it and practicing it verbally. Which is how anyone illiterate has to learn it. Consequently, you do not get to be able to read and write it 'for free'.
Nowadays, especially since we are so literate (eg this forum!), we use a lot more texts. Ars does not allow this as a method. I do not have a problem with that, but I do think that picking up more languages should be a lot easier.
I am currently putting together a plot-line using the Theban Tribunal book. I want magi able to use/read/write Latin as well as Greek and, if possible, Arabic. And translate each of these.
Getting enough xp for a magus to have a score of 3 in AL is doable (and something that most magi should be happy learning more of anyway). Trying to scrape up enough xp for a starting magus, fresh form gauntlet, to have at least 4 in two languages, let alone 3, is not feasible without skimping too much on his other skills. I'm thinking about instituting a minor house rule to reduce the learning total if your language score is less than 4, rather than the RAW statement that 'you cannot study from texts at all' (p165 core rules, under 'Books').
With exposure in the rules only giving 2 xp per season, that will take 25 seasons to get the required 50 xp for a score of 4. Practicing the language full-time with native speakers gives 8 xp per season, or just over a year and a half. Hiring an expert teacher will be quicker.
And yet, picking up languages is actually fairly easy if you immerse yourself in the culture for a while, simply from exposure whilst still being able to hold down a full-time job in real life! (I've done this myself, and I don't have any special knack for languages.)
Perhaps Living Languages should be an accelerated ability? What do you all think?
To be sure, in Medieval times many people must have learned languages orally and never picked up literacy in them. That would have been a lot less common for dead languages, which follow the same rules in the game if I remember correctly. I like to think of it in the abstract, with any literate character automatically taking the trouble to learn how to read when he picks up a new language. If you want to keep it granular and limit it to just speaking, I might agree with using accelerated abilities.
In any case, the character set is the simplest part for Western languages. I'm guessing that the rules were written by someone who didn't know any foreign alphabets, or perhaps who had learned a difficult Asian script. Learning Greek or Cyrillic characters is the easy part of learning a language that uses them.
If you want to go somewhere in between Abilities and Accelerated Abilities, you could grant everyone the effects of the Linguist Minor Virtue for free, and give +50% for actually taking Linguist.
Chris
And thank you for the supply of answers and ensuing discussion 
I haven't looked at A&A in quite some time; that probably explains why I couldn't find the answer.
While i rather agree with your rules-y direction, i simply can not even the slightest agree with your above statement.
Using myself as example, it was when i totally quit trying to learn the alphabet that i finally was able to start learning some Japanese, something that previously eluded me for a long time, and in retrospect i can say that that was because it´s so damned standard to try to learn kanji or at minimum hiragana as part of the language, which i was utterly useless at, distracting and preventing me from actually learning the language itself.
OTOH, i´m a very verbally focused person, my friend learned the kana´s and some of the kanji almost with ease but doesn´t even have a tenth of my vocabulary and general understanding.
Well, as I speculated above, the rules might be written to simulate learning difficult Asian scripts. I know close to zero about Japanese, so I'll take your word for the difficulty. I would imagine it's much more common for AM characters to learn Slavic or Greek scripts, which are not especially difficult.
The big problem in my view is that you have Katakana, Hiragana, both consisting of over the same 70 letters and both sets of letters most often representing 2 or 3 letters from the latin alphabet, with Hiragana being the main and Katakana being used for certain categories of words and for foreign or loan words.
And then there is Kanji, which is essentially the same as the logographic/pictographic characters that originate from Chinese writing. Of which there´s a few thousand of that are in common use in Japan today, with a total number of over 100.000.
That, however is STILL NOT all... There´s also the Furigana which are "helpers", essentially a reduced size Hiragana or Katakana, placed with Kanji signs as pronounciation assistance. Which can make a line of Kanji look even stranger. (that still isnt all, but it is the most common things at least)
Anyway, i think the AL score really must represent alphabets rather than individual languages as otherwise it becomes nearly impossible to be a "great linguist". And from that, as long as you have proficieny in the alphabet(s) used, regardless of AL score, you should be fine in my view. Otherwise it just gets strange.
Still, the AL limitation with alphabets is still a problem if you have a character who sets his mind on travelling far and wide, because if he then starts to learn languages that all have separate alphabets, matters can start getting REALLY strange.
IIRC, last time it happened i think we solved it by adding a "Write languages" Ability with Art style score progression.
Have also tried using the variant from older editions, with each language having its own Ability(Art progression of course). That messed up a bit though.