Speech (Fallout: New Vegas)

Speech is a skill $$ It determines the amount to succeed in a Speech challenge.

Math

 * $$\text{Initial level}=2+(2\times\text{Charisma})+\left\lceil\frac{\text{Luck}}{2}\right\rceil$$

Example: A starting Charisma of 5 and Luck of 5.
 * $$2+(2\times5)+\left\lceil\frac{5}{2}\right\rceil=15$$

Speech no longer has a '%' chance of working as $$ It now works 100% of the time if one has the right Speech skill, which makes it impossible to save and load to bypass Speech challenges. A Speech challenge beyond the player's ability will usually have one dialogue option, and another when it is within the player's ability. Speech is an extremely useful skill in New Vegas, since it can frequently allow the player to avoid fights or accomplish quests more easily.

Ways to increase Speech

 * Permanent
 * Leveling up (+15 or +17 with Educated)
 * Lying, Congressional Style (+3 or 4 with Comprehension)
 * Empathy Synthesizer (+2 depending on current Charisma, a perfect Charisma of 10 will see no benefit.)
 * Tag! (+15)
 * Good Natured (+5)
 * Skilled (+5)
 * Complete the Lonesome Road DLC.
 * Temporary
 * Meeting People (+10 or 20 with Comprehension)
 * Mentats (+2 depending on current Charisma, a perfect Charisma of 10 will see no benefit.)
 * Party Time Mentats (+2-10 depending on current Charisma, a perfect Charisma of 10 will see no benefit, can be stacked with Mentats)
 * Light Switch 02 Upgrade: "Mood Lights" (+5 up to +9 depending on current Charisma)
 * Absinthe/Beer/Irradiated Beer/Jake Juice/Scotch/Irradiated Scotch/Vodka/Whiskey/Irradiated Whiskey/Wine (+2 depending on current Charisma, a perfect Charisma of 10 will see no benefit.)
 * Eating an NPC after the perk Meat of Champions is acquired using the Cannibal perk (+2 depending on current Charisma, a perfect Charisma of 10 will see no benefit; potentially +3 if current Luck is even and not 10.)
 * Sexy sleepwear (+2 depending on current Charisma, a perfect Charisma of 10 will see no benefit.)
 * T-51b power armor helmet (+2 depending on current Charisma, a perfect Charisma of 10 will see no benefit.)
 * Daniel's hat (+5)
 * Sheriff's duster (+2 depending on current Charisma, a perfect Charisma of 10 will see no benefit.)
 * Bounty Hunter Duster (+2 depending on current Charisma, a perfect Charisma of 10 will see no benefit.)
 * Regulator duster (+2 depending on current Charisma, a perfect Charisma of 10 will see no benefit.)
 * Vault jumpsuit (+2)
 * Benny's suit (+5)
 * Caesar's Armor (+5)
 * Dean's tuxedo (+5)
 * President Kimball's suit (+5)
 * Pre-War businesswear (+5)
 * Vera's outfit (+5)
 * Naughty nightwear (+10) (potentially +11 if current Luck is even and not 10)
 * US Army General Outfit (+10)