The original regulations of the Patent Cooperation Treaty (PCT) provided for publication in only five (5) languages, English, French, German, Japanese, and Russian.
Since then, PCT Rule 48.3 has been amended to include Spanish (1985), Chinese (1994), and Arabic (2006) as additional languages of publication.
At its 36th session in September-October 2007, the PCT Assembly adopted, with effect from January 1, 2009, an amendment to PCT Rule 48.3(a), thereby adding two new languages of publication (Korean and Portuguese) to the PCT.