ICAO English is commonly used name of language proficiency qualification introduced by International Civil Aviation Organization. ICAO English mandating the pilots to attend specific language proficiency exam in order to evaluate their language skills in using of English language in situations requiring other than standardized aviation phraseology.
With regards to EASA flight crew licenses in most of the cases the wrong naming is used. ICAO English is used also to describe the language proficiency endorsement required by EASA. In such case both - ICAO English and EASA English are evaluated at the same time, thus the correct wording should be language proficiency or EASA English.
Procedures for language proficiency assessments are throughly described in ICAO Doc 9835.