In terms of sounds, Czech possesses a glottal stop before initial vowels, Slovak uses long vowels less frequently, and Slovak possesses long forms of the consonants "r" and "l" for when they function as vowels.
Czech possesses a glottal stop before initial vowels uses long vowels less frequently, and Slovak possesses long forms of the consonants "r" and "l" for when they function as vowels. This is in terms of sounds. Initial vowels are Slovak.