Rettskrivingsregler for pinyin

Regler for bruk<svg fill="currentColor" aria-hidden="true" preserveAspectRatio="xMidYMid meet" height="1em" width="1em" class="c-icon css-r1jyi6-StyledChevron eqszgqi0" viewBox="0 0 24 24" data-license="Apache License 2.0" data-source="Material Design" style="vertical-align:middle">