お早うございます[ohayougozaimasu] good morning
一刻も早く[ikkokumohayaku] immediately
いち早く[ichihayaku] promptly
口早[kuchibaya] rapid talking
最早[mohaya] already

時期が早い[jikigahayai] before scheduled
時期尚早[jikishousou] premature
時機尚早[jikishousou] before its time
早手[hayate] gale
手早い[tebayai] nimble

逸速く[ichihayaku] promptly
音速[onsoku] speed of sound
加速[kasoku] acceleration
加速運動[kasokuundou] accelerated motion
加速度[kasokudo] acceleration

快速[kaisoku] high speed
快速電車[kaisokudensha] high-speed train
角速度[kakusokudo] angular velocity
急速[kyuusoku] rapid (e.g. progress)
減速[gensoku] deceleration