Anglo-Norman language general use of the word "acre" for land measurement in Normandy until metrication in the 19th century, but these words are probably linguistic traces of Saxon or Anglo-Scandinavian settlements between the 4th and the 10th centuries in Normandy. Otherwise the direct influence of English in mainland Norman (such as "smogler" - to smuggle) is from direct contact in later centuries with English, rather than Anglo-Norman. When the Normans invaded England, Anglo-Saxon literature had reached a very high level of development. The important Benedictine monasteries both wrote chronicles and guarded other works in Old English. However, with the arrival of the
Anglo-Norman language French was not standardised as an official administrative language of the kingdom of France. Middle English was heavily influenced by Anglo-Norman and, later, Anglo-French. W. Rothwell has called Anglo-French 'the missing link' because many etymological dictionaries seem to ignore the contribution of that language in English and because Anglo-Norman and Anglo-French can explain the transmission of words from French into English and fill the void left by the absence of documentary records of English (in the main) between 1066 and c. 1380. Anglo-Norman morphology and pronunciation can be deduced from its heritage in English. Mostly, it is done in comparison