Crashing diacritics: їїfö!

[ctrlcctrlv]

I=0; pango-view --markup <(
    for L in $(pango-list |grep Besley|grep :|awk 'BEGIN{FS=":"}{print substr($1, 3)}' | sort | uniq);
    do
        I=$(($I+1));
        printf '%s' $'<span font_desc="Besley '"$L"'" size="72pt">їїfö! ÏÏFÖ! </span>';
        [[ $(bc <<< "$I % 7") == 0 ]] && echo; done
)

Despite їїfö being a nonsense word, both sequences appear in real words:

• її — Ukrainian for "her".
• mérfölddel — Hungarian for "by miles".