My unimplemented house rules for languages
Rudimentary Language
For all classes except bard, Speak Language is a Cross-Class skill taking two points. If only one point is spent on a language, the character is considered to have rudimentary understanding of a language, knowing a limited vocabulary and very few grammatical rules. He will be able to understand a speaker only by making an intelligence check. The difficulty class is as follows:
DC: 10 Speaker is attempting to speak in simple terms to aid understanding
DC: 15 Normal conversation
DC: 20 Speaker is deliberately confusing understanding.
DC: +5 Inherently complex or difficult subject
DC: -5 conversation on the following subjects: language fluency, food and drink, insults, learning names, locating conveniences.
If the DC is failed by more than 5, the listener has misunderstood the speakers statement in a way which reverses or changes the meaning in a deleterious manner. A DC 15 + failed check difference Will Save will alert the character to the potential of his mistake before acting on it.
The same DC applies to a character with rudimentary language attempting to communicate with a proficient speaker. The proficient character will not be confused by mistakes made by the speaker but will merely fail to gain knowledge of what was conveyed.
Speaking a rudimentary language in combat is move-equivalent action instead of a free action.
When reading, rudimentary language knowledge will be useless unless the speaker is proficient in a language in the same alphabet as the rudimentary language. If the alphabet is known, then the same DCs apply to understand any given text up to 20 pages in length. 5 ranks in Decipher Script will give a +2 synergy bonus modifer to the intelligence check to understand the text.
Skill checks DCs that are affected by rudimentary language
Diplomacy checks DC +5;
Innuendo checks DC +10
Rudimentary Common
The "common tongue" is frequently understood as a "trade language" that most people know in addition to any local dialect that they are native speakers of. To better reflect this understanding, the following rules are used:
All character are proficient in their racial language (if non-human) or human dialect and know common only rudimentarily. It still takes 2 full skill points to learn common at a "proficient" level, or proficient common may be selected as one of the bonus languages for high intelligence.
Any given race designated as speaking common in the core rules has a 20% chance of not speaking it at all, a 50% chance of speaking it only rudimentarily, and a 30% chance of speaking it proficiently. In non-urban ares the probabilities are 40% non-speakers, 50% rudimentary speakers and 10% speakers. Innkeepers, merchants and authorities are always at least rudimentary speakers. There is only a 20% chance that any native of an uncivilized area is a rudimentary speaker of common
some other ideas
Special Languages
Abyssal
Initimidation checks in Abyssal are at +2. Speakers receive a -2 to will saves versus demons.
Aquan
This language can be spoken underwater without penalty.
Auran
Speakers of this language may communicate at ultreasonic freqencies, adding 10 to the listen check.
Celestial
It is impossible for mortals to lie when speaking this tongue.
Draconic
+2 circumstance bonus to spellcraft checks for verbal spells and deciphering scrolls.
Druidic
Oaths taken in druidic (voluntary and with full knowledge) have the effect of a Geas for nonperformance