2.2 Two Major Sources of Variations of Grammar

Diachronic variations: historical, time-related

Synchronic variations: related to different regions (regional dialects), socioeconomic class (dialect, jargon, slang, etc.), or register (spoken vs. written)

Ferdinand de Saussure (1857-1913), 'the founder of modern linguistics', theorized this pair of concepts in his posthumous book Course in General Linguistics (1906).