Speech

Speech is a Fallout, Fallout 2, and Fallout 3 skill. In Van Buren, it was divided into two skills - Persuasion and Deception.

The ability to communicate in a practical and efficient manner. The skill of convincing others that your position is correct. The ability to lie and not get caught.

Fallout and Fallout 2
Initial Level: Starting Speech skill is equal to 25% + (2% x Charisma). Average characters will have a 35% skill.

Speech skill was in the first draft of Fallout Tactics skills, but was eventually left out.

Fallout 3
Occasionally, you will be presented with a Speech Challenge. A Speech Challenge is a response preceded by the word “Speech” and the percentage chance of success (e.g., [Speech 25%]); the higher your Speech skill, the greater the chance of success.

Succeed in a Speech Challenge, and you’ll achieve the results indicated by the response. Fail a Speech Challenge, and future Speech Challenges with that character will be more difficult.

Having a weapon drawn will influence your percentage to succeed at a speech challenge.

Charisma and Speech skill both influence your chance of success. For example, when trying to calm Bryan Wilks down, a Charisma 6 character with 53 Speech might wear a Vault jumpsuit (+2 Speech) Dirty Business Wear (+5 Speech) or Sexy Sleepwear (+1 Charisma, which increases Speech to 55 indirectly). Charisma 6 and Speech 55 gives a 76% chance of success, Charisma 6 and Speech 58 gives an 80% chance of success, and Charisma 7 and Speech 55 gives an 82% chance of success. While it is possible to gain 100 Speech with Charisma 1, if you want the Silver Tongued Devil achievement, a high Charisma is as important as a high Speech skill.

From time to time you may also be presented with dialogue options where a word appears with no percentage (e.g., Strength or Lady Killer/Black Widow). In this case, this is a dialogue option that is available to you because of the level of the indicated S.P.E.C.I.A.L. statistic, Skill, or Perk and you will always be successful when selecting it. You only get one chance at each Speech Challenge, so if encounter one has a low percentage to succeed, you may want to exit dialogue and try the Speech challenge at a later time, after you’ve raised your Speech skill.

In order to gain a 100 in the speech skill, without directly putting skill points into it, it is necessary to only have a -2 to start with. 132 points can be obtained in game from items, perks, and quests.

As an alternative to using precious perks to maximize this mostly useless skill (see saving strategy below), one can wear the Naughty Nightwear and Button's Wig clothing items for a +20 bonus. All together, without a single perk (Other than comprehension, which all characters should get), one can acquire +90, and with the minimum of 4 to begin, one can have 94 skill with no perks/skill/S.P.E.C.I.A.L. points invested.
 * +10 to your speech skill can be earned as a possible reward from the quest Oasis. You must pass the speech check with Sapling Yew regarding what Harold is afraid of.
 * +10 for the Speech Bobblehead.
 * +46* collecting all 25 Lying, Congressional Style books.
 * +15 for the Speech perk. (+5 for each level of 3 total.)
 * +2 for the Paradise Lost book from Tulip in the Underworld.
 * +15 for the Tag! perk
 * +2 from Charisma bobblehead
 * +30 from the Impartial Mediation perk with Neutral Karma.
 * *(+2 per book with the Comprehension perk. Normally +1 without the perk. Two books are mutually exclusive, meaning only 23/24 books can be attained, and the 23rd requires the contract killer perk, so good characters may only be able to get 22/24)

Strategy
In addition to counting towards the Silver-Tongued Devil achievement, successful Speech Challenges in Fallout 3 can yield the player any number of benefits: they may be rewarded with a significant increase in caps for completing quests, keys or passwords, karma, experience points, or even the chance to peacefully resolve some quests without the need for violence. However, a strong argument can still be made that -- due to how Speech Challenges are presented and implemented in the game -- the Speech skill itself is the least important in the game.

Unlike Barter (which will affect a great many transactions in the game), Speech skill will only affect specific dialogue options for the NPC's that present Speech Challenges in the game. Putting a large number of skill points into Speech -- or, even worse, selecting it as a Tag Skill -- assures that your character will be very, very adept with a fairly uncommonly occurring game mechanic.

Furthermore, whereas combat skills might increase your accuracy with a specific weapon, odds are very good that if you miss, you'll get another shot. Literally. With Speech Challenges, you only have one chance. Since even a high Speech skill will not guarantee success, if you're serious about succeeding in a Speech Challenge, you're probably going to be careful enough to save the game before rolling the dice anyway. Using this strategy, a higher Speech skill will only increase your probability of success, which translates to theoretically fewer game reloads until you succeed. Considering this, spending ten points to increase from a Speech of 30 to a Speech of 40 is likely to be completely unnoticeable in actual practice.

It is not difficult to save the game right before initiating dialogue with most NPC's in the game. In circumstances where an NPC will initiate conversations with you that can include Speech Challenges (such as Bryan Wilks, Lug-Nut, or Goalie Ledoux), these NPC's will only appear under predictable circumstances (nearing Grayditch, obtaining the Naughty Nightwear, or arriving at the Red Racer Factory); thus, saving the game just before encountering these NPC's will allow you to use the same strategy listed above.

For NPC's who can present multiple Speech Challenges -- such as Bryan Wilks or Vance -- it is possible to choose the option to stop speaking to them after succeeding in the first Speech Challenge, save the game, and then talk to them again to attempt the second Speech Challenge.

=Appendix=

List of Fallout 3 Speech Challenges
For the Silver-Tongued Devil achievement, you need to win 50 speech challenges. For this purpose this page will contain a list of those speech challenges. Please continue to add challenges here.

Cheat
There is a glitch where you can talk to pappy and keep performing the speech challenge over and over again, this will help you gain the achievement Silver-Tongued Devil and also get you unlimited exp. note. you have to speak to Bittercup first. This works on all versions.
 * Note:This glitch is patched in the latest version of the game.

A similar (as yet unpatched) glitch occurs in Little Lamplight. When speaking to Knock Knock it is possible to repeatedly tell her that her joke is funny for esentially unlimited XP. (Ask about morale to start the tree that leads to the joke)