Magical Languages (and Hedge Magic)... D&D Houserules

The languages of Outsiders, Elementals and other natural forces contain a portion of their magic. Anyone with the knowledge of that tongue may use that magic.

When using this system it is recommended that characters, in general, have fewer 'free' languages: a single bonus language for having an intelligence score above a certain threshold. To balance, all mundane languages also include basic knowledge of courtesy to grant a +2 bonus on Diplomacy checks with members of that culture.

Abyssal - (Blasphemy) Uttering Abyssal anywhere not inherently evil causes a palpable sense of dread: All non-evil creatures who hear the words, and those within 30ft (including deaf creatures) must make a Will save or be Shaken until the speaker's next turn. The DC is equal to 10 + Charisma Modifier. A creature that passes its save is immune to further use by the same speaker for 24 hours.

Aquan - (Knowledge) A character may take a minute to tell one liquid from another by listening to it carefully with a DC15 Wisdom check. This will allow them to detect water borne contagion or poison - although a Knowledge check is still required to identify which contagion or poison specifically. They may also coerce any open body of water (such as a puddle) in to displaying any scene reflected in its pool with a DC15 Charisma check.

Auran - (Buoyancy) The character may spend a Swift Action to add their Charisma modifier to Jump checks until the start of their next turn.

Celestial - (Blessing) As a Swift Action the Celestial may be used to rally the spirits of those who hear it, providing non-evil creatures a reflexive save against any ongoing Fear effects. Any Undead who hear it (and mindless or deaf undead within 30ft) must make a Will save vs DC10 plus Charisma Modifier or be Shaken until the end of the speaker's next turn. This is not a Mind Affecting effect and mindless undead fail automatically.

Draconic - (Arcane Tongue) Any Arcane spell with Verbal Components has its Spell Save DC increased by 1. The character may choose to add Verbal components to any spell that does not normally have them to benefit from this. This also provides the +2 bonus on social skills that a Mundane language would when dealing with Draconic creatures.

Ignan - (Pyrophilia) The character may create fire or light without tinder. They may use Light as an at-will Spell Like Ability (caster level 1) and can spend a Swift Action to ignite any flammable mixture (such as gunpowder) within 100ft by speaking Ignan, granting the object a Will save against DC10 + Charisma Modifier (noting that an unattended item will automatically fail).

Most alchemical preparations are sealed against the air and will not usually ignite when properly stored.

Infernal - (Pact) Any agreement, deal or contract made in Infernal, orally or written, will bind those who made it to the letter of the agreement per a Geas spell (no save is allowed). The caster level of the spell is the highest character level of those party to the agreement. An agreement is defined as one in which both parties enter into knowingly, i.e. they cannot be 'tricked' into agreeing unintentionally, but that agreement may be based on information that is out of date or wrong.

As an example, making an agreement to have someone brought back to life without realising that individual betrayed or planned to betray them.

By petition a deal may be brought for arbitration before a court of 12 sitting Fiendish judges elected by the machinations of infernal politics. As would be expected the court will swiftly hear the facts of the case before ruling in favour of hell's (and its denizens) interests - having little reason beyond procedure to care for mortal pleas - but under exceptional circumstances they may be persuaded by bribery or blackmail.

Sylvan - (Commune) A character may use their knowledge of Sylvan to converse with an animal. The ability to communicate with the animal is not automatic and requires a Handle Animal check against DC15 to understand the animal and make oneself understood. You may also use Handle Animal with a non-intelligent creature in the same way one would use Diplomacy with an intelligent creature.

Terran - (Till) As a Swift Action the character may cause earth and rock to twist and shape - for each point of Charisma Modifier (minimum 1) a single 5ft space within 100ft becomes Difficult Terrain until that character's next turn. When using this power the character also applies their Charisma Modifier as a bonus to CMB and CMD when making and resisting Trip attempts.

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Edit (30th March 2013): Changed Save DCs to be in-line for a Cantrip. DC10+Cha mod. Abyssal now affects non-evil only, Celestial grants reflexive saves to non-evil only.

Edit (30th March 2013 @ 1800GMT): Rewrote Auran to affect Jump rolls only, but no longer require a Charisma check. Rewrote Terran to provide a bonus to resist Trip manoeuvres and changed the duration to start of the character's next turn, not end of.

Edit (31st March 2013 @ 0330GMT): Rewrote Terran to provide Armour Resistance and remove the Attribute Check. Slightly concerned it might still be the no-brainer of the set to cause sheenanigans when interacting with Class Defence rules however.

Edit (31st March 2013 @ 0400GMT): Rewrote Terran again, changed the power dramatically.