In the latest twist to Pennsylvania's voter-ID litigation, a brief filed Wednesday says Asian Americans are especially vulnerable to being barred at the polls because of name customs and language barriers.

In particular, the brief notes that Asian family names often precede given names, which can create confusion for those unfamiliar with the practice, and that clerical errors can crop up on documents when Asian characters are transliterated.

The friend-of-the-court brief by the Asian Pacific American Bar Association of Pennsylvania and the Asian American Legal Defense and Education Fund supports a lawsuit that seeks to block implementation of the Pennsylvania law ahead of the November election.

On Aug. 15, Commonwealth Court Judge Robert E. Simpson Jr. refused to grant a preliminary injunction. The brief asks him to reconsider.

It says the photo-ID law "gives poll workers unfettered discretion" to determine whether the name on an identity document "substantially conforms" to the name on the voter rolls, but does not define conformity, offering no guidance on "the acceptable range of errors."

Asian Americans are the fastest-growing minority in the United States. About 400,000 Pennsylvanians identified themselves as Asian in the 2010 census, according to the brief, and more than 70 percent are naturalized citizens.

To get U.S. citizenship, they passed a basic English proficiency test, but many still struggle with the language.

By not translating key voter-ID documents into the languages of the state's largest minority groups - Spanish, Chinese, Vietnamese, Korean, and Khmer - the brief alleges, the commonwealth has not met its federal obligation to avoid discrimination on the basis of national origin.

In a July 20 announcement, the state said it would offer voter IDs to eligible people who are not able to provide the documents necessary to obtain a Department of Transportation ID.

"The commonwealth's belated and ad hoc approach . . . underscores why a preliminary injunction is necessary," the brief states.

A spokesman for Attorney General Linda Kelly, who is representing the state, was not immediately available.

Contact Michael Matza at 215-854-2541 or mmatza@phillynews.com.