AUSTIN, Texas (AP) — A court has upheld that Texas violated the federal Voting Rights Act following a challenge by a woman who spoke limited English and couldn't use her son to help cast a ballot.

The ruling this week by the 5th U.S. Circuit Court of Appeals honed in on a little-known portion of the Voting Rights Act that allows assistance to people who have disabilities or difficulty reading or writing.

A separate Texas law says interpreters must be registered to vote in the county where they're helping. That stopped an India-born woman from having her son interpret her ballot in Williamson County in 2014.

U.S. Circuit Judge Patrick Higginbotham wrote that Texas the law limited "the right to the act of casting a ballot."

The case now returns to a lower court.