The aim of the study was to validate an instrument and propose standards to measure the language skills of school adolescents. 2270 adolescents (1134 males and 1136 females) in the region of Maule (Chile) was studied. The age range is between 10 to 18 years. The validated instrument has three categories (verbal, paralinguistic and non-verbal) and a total of 26 items. The instrument showed to be valid after the exploratory analysis and Cronbach α (0.86 to 0.88) showed highly reliable values. The LMS method to develop percentiles, let p10, p50 and p90 calculated by age and sex. The instrument measures developed language skills valid and reliable also adopted cutoffs allow diagnose and adolescents by age and sex. These results suggest the use and application of the instrument as an everyday tool in social, cultural and educational contexts.