Is an English translation of a foreign application always required?
No, an English translation of a non-English language foreign application is not always required. According to 37 CFR 1.55(g)(3), an English language translation is only required in specific circumstances:
An English language translation of a non-English language foreign application is not required except: (i) When the application is involved in an interference (see § 41.202 of this chapter) or derivation (see part 42 of this chapter) proceeding; (ii) When necessary to overcome the date of a reference relied upon by the examiner; or (iii) When specifically required by the examiner.
If a translation is required, it must be filed together with a statement that the translation of the certified copy is accurate.
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Topics:
MPEP 200 - Types and Status of Application; Benefit and Priority,
Patent Law,
Patent Procedure