Charisma and Speech checks

Hey Community, I know this is a frequent question but I couldn’t find specific information, I know charisma is not important for New Vegas but I’m unsure if there is a big negative impact on dumping charisma for Fallout 3 in TTW - it seems to be more important for the Capital Wasteland part of TTW but I’m unsure exactly how important. I’m not planning to play with companions but I don’t want to handicap my speech focus build by leaving Charisma at 1. it would be nice to have points free for strength with ammo weight etc. Can I leave charisma at 1 and still pass all speech checks if I level my speech to 100? Thanks in advance !