BRUSSELS (Reuters) - The European Court of Justice could cut costs and speed up verdicts by letting judges speak English rather than only in French, an EU audit showed on Tuesday - but a plan to let them has been stymied by Brexit.

The Luxembourg-based court is a bogeyman for British critics of the EU and negotiations on the 2019 withdrawal from the European Union are deadlocked over London’s insistence the ECJ should have no future say in Britain. Yet before last year’s Brexit referendum it was looking at embracing English more.

“This assessment has not yet been finalised because of the uncertainties related to the outcome of the Brexit process,” the European Court of Auditors (ECA) said in a report.

The Court is a bastion of the French language among European Union institutions where English has become ubiquitous.

ECJ rules, intended to avoid linguistic arguments over the law, force judges to use French in their deliberations and written submissions and verdicts must be in the bloc’s once dominant tongue, even though English is now the most common of the 24 official EU languages in which cases can be filed.

The ECA did not say how much of the Court’s 400-million-euro ($470 million) annual budget could be saved by allowing the use of English. But some lawyers working at the ECJ say translation into French, in which only 13 percent of cases are actually initially filed, adds to delays in getting judgments.

Brexit has raised some questions about the status of English in the EU as a whole, since once Britain leaves it will not be the official EU language of any member state. It is an official language in Ireland and Malta but countries can only nominate one for EU use and they chose Gaelic and Maltese respectively.

However, EU officials do not seriously imagine that English is threatened as a working language. At the Court, even when Britain ceases to be subject to its judgments, many cases will continue to involve multinational companies and many of those choose have their pleas dealt with principally in English.

In a reply included in the ECA report, the Court said the time taken for rulings has fallen in the past decade despite an increased caseload and that discussions will continue on a language regime that is chosen on the basis of its efficiency.