Learning about the language invovles the history of that language, the etymology of words in the target language as well as the formation of words over time and the changes in the language. For instance, if one studies English, one learns the story of English, the story of migrations, settling, and invasions and war. Old English began with the Angles, a people who originated in a section of Denmark called Angeln. The language of the Anglo-Saxons is what became the language of England (Saxon being the name of the German conquerors). Then, in 1066 the Norman Conquest had a tremendous impact upon the Anglo-Saxon language. Since the Norman l hadl but destroyed every Anglso-Saxon lord, French, the language of Normandy became the official language, and for nearly 300 hundred years the literature of England was published in French. With Chaucer's The Canterbury Tales, written in Old English, French was replaced as the language of the literature. Old English eventually evolved into Middle English, and then Modern English.
Learning the language is the acquisition of vocabulary, and speaking and writing skills. This involves the formal study of the language per se and the attainment of fluency and pronunciation.