The people who moved north (North Germanic) and stayed, spoke Danish, Faeroese, Icelandic, Norwegian, and Swedish. The Proto Germanic speaking tribes that moved west (West Germanic) developed German (high and low), Dutch, Flemish, and Frisian.

Frisian is the most closely related language to English.  Frisian was formerly spoken from the province of North Holland in The Netherlands to Schleswig in northern Germany.  Frisian is now spoken only in three small areas, each with its own dialect. West Frisian is spoken in the province of Friesland in The Netherlands and is considered an official language by the Dutch government. East Frisian (Saterfreisen) is spoken in the Saterland, a municipality in the German state of Lower Saxony, west of Oldenburg. It is the smallest minority recognized by the German government. North Frisian is spoken along the North Sea coast of Germany and on the Frisian Islands. Written records in Old Frisian date from the end of the 13th century.

 Many features of Old English (OE) look a lot like German because the roots of Old English are in Proto-Germanic, a subset of the Indo-European (IE) family of languages.  Like modern German, all the nouns in Old English, including inanimate objects, are neutral, feminine, or masculine. Old English has no Latin or French words, there are hundreds of strong (irregular) verbs, the word order is not fixed, and nouns change their form or endings when they are the subject or the object or if they are possessive etc.

The first inhabitants of Britain were the Celts. In 55 B.C. when the Roman army under Julius Caesar first attempted to invade Britain, English did not exist. The Romans never penetrated far into Scotland or Wales. By the end of the Roman occupation in 410 A.D., the Celts, who the Romans had eventually converted to Christianity, were too weak to defend themselves against the Picts/ Scots from the north and had started to look for allies.

The origin of the word “English” begins in 449 A.D. when according to the Anglo-Saxon Chronicle, established under Alfred the Great (871-899), the Celt King, Vortigern, promised land in the southeast to Anglum (Angles) if it helped the Celts defend themselves against the Picts / Pictish (northern Scots).  The Celts also sought aid from the regions of Ald Seaxum (Saxony) and Iotum (Jute). These tribes— the Angles, Saxons, and Jutes — lived on the coast of West Germany and Denmark.

 Anglo-Saxon English (Old English) came because the Saxons settled in the south of Britain and the Angles in the north and east.  These Germanic immigrant tribes formed the Anglo-Saxon society and over time their languages coalesced into Old English.  Old English was spoken between the 5th and 11th centuries and began to appear in writing during the early 8th century.  The Celts eventually were forced to settle in the highland regions of Cornwall, Ireland, Scotland, and Wales.

Speakers of Old English called their language Englisc, they were Angle(s), Angelcynn or Angelfolc and their home was Angelcynn or Englaland (land of the Angles). Some of their words e.g. I, me, you, tall, short, food, water, wood, stone, work, earth, be, hound, overweening, betwixt, fortnight "feowertyne niht" formed the core of English. ...

The Anglo-Saxon history of England ended when the Anglo Saxons were finally conquered by the Normans from Northern France under William the Conqueror/ Guillaume le Conquérant in 1066 in the Battle of Hastings.

After the Norman Conquest, The Normans made major changes to the vocabulary and the spelling. French became the language of the court (aristocracy), the government, and the law. Norman French formed the 'upper layer' of the society (freedom and liberty; work and labour; truth and veracity) and Anglo-Saxon was spoken by the masses. That is why English ended up having two words for many things that languages like French and German have just one for (German: haus; French: maison; English: house and mansion). Vive la difference!