Some portions of society have developed ‘secret’ languages as a means to communicate without disclosing their dialog to others. In all cases, these messages are simplistic. Secret languages are generally not capable of discussing religion or politics. Instead, they are used to mark areas as dangerous, identify safe-havens, show membership in a guild, and other simple messages. They are more than a simple sigil or symbol, but less than a full-blown language.
Mechanically, all secret languages work the same. Secret languages do not take up a language slot nor do they require any skill points in Linguistics. A class or race grants access to a “secret” language for free. Fluency in any secret language is measured at a skill level equal to the level gained in the class that granted it. As a rule of thumb, the skill level is also the number of words that can be included in a typical message. Some secret languages are written, while others include - or are entirely - hand-signs. Those who are not fluent can sometimes determine the usage of a secret language using skill checks as outlined here.
Those who are fluent in a secret language can send or receive any message in that language whose skill level is equal to or below their own. They must succeed at a skill check to send or receive higher skill-level messages. The DC is 10+skill level of the message, against a D20+the skill level of the user + any bonus. Those who are not fluent in a secret language can make a Linguistics check against the same DC to determine if a particular secret language is being used, although they cannot automatically decipher the message. Regardless of whether one is fluent or not, a synergy bonus applies to their check as described below.
The "Secret" Languages include:
‘Thieves Cant’ is a language known only by Rogues and Assassins. It can be either written, a sign language, or a combination of the two. Translation/Detection: a synergy bonus of +2 applies to any check regarding Thieves Cant with 5 or more ranks in Knowledge: Local. Translation is possible withComprehend Languages only for that part of a message that is in written form.
‘Draconic Prophecy’ is a language known only by Dragons. It can only be written and usually appears as complex glyphs. Translation/Detection: a synergy bonus of +2 applies to any check regarding Draconic Prophecy with 5 or more ranks in Knowledge: Arcana. Translation is possible withComprehend Languages, although even then the meaning may not be clear.
‘Druidic’ is a form of communication known only by Druids. It uses an obscure system of patterns, colors and symbols, with messages often appearing as nothing more than an arrangement of stones or other objects. More permanent messages can appear as carefully tended groves of trees or in the winding path of a river. Some Druids wear a pattern on their clothing as a hidden message.Translation/Detection: a synergy bonus of +2 applies to any check regarding Druidic with 5 or more ranks in Knowledge: Nature. Translation is not possible by non-Druids, and Druids are forbidden to teach this language to any non-Druids.
‘Venorik,' which means 'silent' in the Morvanima dialect, is a sign language known only by Morvanima Elves. Never found in written form, it is passed down from parents to children only among the Morvanima. Translation/ Detection: a synergy bonus of +2 applies to any check regarding Venorik with 5 or more ranks in Knowledge: Fey or Local. Translation is not possible, and Morvanima are forbidden to teach this language outside their race.
‘Shadowsign’ is a secret sign language used by an organization called The Shadows of the Sunlit World, more commonly known as The Shadow Guild. This is a secret organization believed to be controlled by Gnomes who wish to spy on the upper world [see the Tears of Blood SupplementOrganizations in the World of Ursoule]. It is taught only to members of the Guild. Translation/ Detection: a synergy bonus of +2 applies to any check regarding Shadowsign with 5 or more ranks in Knowledge: Arcana. Translation is not possible, and it is forbidden to teach this language to anyone outside the Guild.Other secret languages may be developed as your DM/GM sees fit. Note that Comprehend Languages can only translate spoken words or written messages, and Tongues can only translate spoken words. Even if translated, the meaning may not be clear. Neither spell can translate sign language. The Linguistics skill also applies only to spoken or written languages.
‘Xoko’ is a secret sign language used by Sorcerers to communicate among themselves. It allows Sorcerers to recognize each other in public and communicate basic messages without drawing Imperial attention. Sorcery is outlawed in most parts of the Empire, and although enforcement is chaotic at best, there are still those who use the law to their advantage. Sorcerers will never teach this language to non-Sorcerers, except perhaps for a few hand signs or words of recognition to their allies.
Translation/Detection: a synergy bonus of +2 applies to any check regarding Xoko with 5 or more ranks in Knowledge: Arcana. Translation is not possible, and it is forbidden to teach the full language to anyone who is not a Sorcerer.
Other secret languages may be developed as your DM/GM sees fit. Note also that Comprehend Languages can only translate spoken words or written messages, and Tongues can only translate spoken words. Even if translated, the meaning may not be clear. Neither spell can translate sign language. The Linguistics skill also applies only to spoken or written languages.
Smiley the 5th level Rogue needs to mark a business as protected by his guild so other Rogues won’t violate the Guilds' promise and ruin the protection racket. As a 5th level Rogue, he has 5 skill levels in Thieves Cant and can read and write up to a 5 word message without having to make a check. However, he also doesn't want any mistakes, so he uses a message that states simply ‘Guild Paid,’ a 2 word message that is readable by any Rogue or Assassin of 2nd level or above. For a 1st level Rogue or Assassin, the DC would be 12 to decipher the meaning, and a 1st level Rogue or Assassin would have a minimum of +1 to their check from their level, plus any synergy bonus.
Furfred the Druid wants to help other wayward Druids. He sets up some simple markers to show the way to shelter and fresh water. The message reads ‘shelter water east’. Any passing Druid of 3rd level or higher would be able to notice the message and read it. At the shelter, Furfred places a longer message, “Avoid west valley, dread spirits, east hills safe.” This has eight words, and so requires a Druid of 8th level or higher, or a Druid who can beat a DC 18 check, to read it. Alternatively, Furfred could have spread his message out into multiple parts, but he would have needed a larger space to ‘write’ all the symbols.
Any character who devotes a Linguistics Skill Point to "Reading Lips" can read the lips of the speaker of any language in which they are fluent. Note that a distant or partially obscured speaker may require a Perception check in order to see what is being said. Reading the lips of a speaker of a language for which the character is not fluent is not possible unless used in combination with Comprehend Languages, Tongues, or similar.
Using Bluff and Sense Motive
Since Bluff can be used untrained, anyone can use Bluff to pass hidden messages to another without others understanding their true meaning. The required DC is 15 for simple spoken messages and 20 for complex spoken/sign messages. If successful, the target automatically understands the message, assuming any spoken part is in a language they understand. If the check fails by 5 or more, the wrong message is delivered. Other creatures that can hear or see the message can decipher it by succeeding at an opposed Sense Motive check against the Bluff result.
Since Sense Motive can also be used untrained, anyone can use Sense Motive to detect that a hidden message is being sent via the Bluff skill. The Sense Motive check is opposed by the Bluff check of the transmitted message. Each piece of information relating to the message that is missing causes a –2 penalty on the Sense Motive check. Succeeding by 4 or less reveals that something hidden is being communicated, but not anything specific about its content. Beating the DC by 5 or more intercepts and understands the message. Failure by 4 or less doesn't detect any hidden communication. Failure by 5 or more might cause false information to be inferred.