Complex sentence: Both katakana and hiragana usually spell native long vowels with the addition of a second vowel kana, but katakana uses a vowel extender mark, called a "chōonpu" ("long vowel mark"), in foreign loanwords.
Split into simpler sentences: Both katakana and hiragana usually spell native long vowels with the addition of a second vowel kana. However, katakana also uses a vowel extender mark, called a "chōonpu" ("long vowel mark"), in foreign loanwords.