The English language belongs to the Anglo-Frisian sub-group of the West Germanic branch of the  The closest living relatives of English are , spoken primarily in Scotland and parts of Northern Ireland, and As Scots is viewed by some linguists to be a group of English dialects rather than a separate language, Frisian is often considered to be the closest living relative.

Lexical differences with the other Germanic languages can arise from several causes, such as natural semantic drift caused by isolation, and heavy usage in English of words taken from Latin (for example, "exit", vs. Dutch uitgang) (literally "out-gang" with "gang" as in "gangway") and French "change" vs. German Änderung, "movement" vs. German Bewegung (literally "othering" and "be-way-ing" ("proceeding along the way")). Preference of one synonym over another can also cause a differentiation in lexis, even where both words are Germanic (for instance, both English care and German Sorge descend from Proto-Germanic *karo and *surgo respectively, but *karo became the dominant word in English for "care" while in German, Dutch, and Scandinavian languages, the *surgo root prevailed. *Surgo still survives in English as sorrow).

Although the syntax of German is significantly different from that of English and other Germanic languages, with different rules for setting up sentences (for example, German Ich habe noch nie etwas auf dem Platz gesehen, vs. English "I have still never seen anything in the square"), English syntax remains extremely similar to that of the North Germanic languages, which are believed to have influenced English syntax during the Middle English Period (eg., Norwegian Jeg har likevel aldri sett noe i torget; Swedish Jag har ännu aldrig sett något på torget).

Dutch syntax is intermediate between English and German  op het plein). In spite of this difference, there are more similarities between English and other Germanic languages than differences (eg. English bring/brought/brought, Dutch brengen/bracht/gebracht, Norwegian bringe/brakte/brakt; English eat/ate/eaten, Dutch eten/at/gegeten, Norwegian ete/åt/ett), with the most similarities occurring between English and the languages of the Low Countries (Dutch and Low German) and Scandinavia.

Semantic differences cause a number of between English and its relatives (eg. English time "time" vs Norwegian time "hour"), and differences in Phonology can obscure words which actually are genetically related ("enough" vs. German genug, Danish nok). Sometimes both semantics and phonology are different (German Zeit, "time", is related to English "tide", but the English word, through a transitional phase of meaning "period"/"interval", has come to mean gravitational effects on the ocean by the moon, the original meaning preserved only in combined forms like Yuletide and betide)These differences, though minor, proclude mutual intelligibility, yet English is still infinitely closer to other Germanic languages than to languages of any other family.

Finally, English has been forming compound words and affixing existing words separately from the other Germanic languages for over 1500 years and has different habits in that regard. For instance, abstract nouns in English may be formed from native words by the suffixes "‑hood", "-ship", "-dom" and "-ness". All of these have cognate suffixes in most or all other Germanic languages, but their usage patterns have diverged, as German "Freiheit" vs. English "freedom" (the suffix "-heit" being cognate of English "-hood", while English "-dom" is cognate with German "-tum"). Icelandic and Faroese are other Germanic languages which follow English in this respect, since, like English, they developed independent of German influences.

Many writtenwords are also intelligible to an English speaker (though pronunciations are often quite different) because English absorbed a large vocabulary from and French, via after the Norman Conquest and directly from French in subsequent centuries. As a result, a large portion of English vocabulary is derived from French, with some minor spelling differences (word endings, use of old French spellings, etc.), as well as occasional divergences in meaning of so-called false friends.