Contrary to some of the answers here Australian, Canadian and American English are varieties of English and not separate languages in themselves, in the same way as Anglo-Irish, New Zealand English and the variety of English spoken in South Africa are. English is a germanic language and although our vocabulary is heavily influenced by Latin, Norman French, Modern French etc, it is still essentially a germanic tongue and so our nearest living relatives are other northern germanic dialects such as dutch, low german and Saxon. However the closest extant language to English is Frisian which is spoken in northern Germany and Holland. Whilst Frisian did not have the same influences of French and Latin, it remains as a curious reminder of how Modern English may have developed if there had been no Norman invasion in 1066. An example is a nursery rhyme I used to hear as a child, "Bread and butter and green cheese is good English and good Friese".
I think everybody better check back a little further in history as Anglo Saxon and Scot were and still are the closes spoken language to english even though the web will say it's Norvegian , now german may have similar words that sound alike and in due time were addapted to english but don't have the same meaning such as the word " Krank " which the spelling was changed to Crank as in crank case , it's original meaning in german translates to " Sick " the other term that is close to english is Mein Freund / My friend / Und = and / Guten = good and so on , and I have Dyslexia no less est Paschar
French/German definitely are the largest influences post Roman invasion with Latin here.
English is considered a Germanic language due to its grammar and pronunciation.
However, there are words with roots from over two hundred languages which we use on a daily basis.Latin arrive and became part of the mix from 55 BC when Caesar's Roman troops invaded and stayed until the mid 5th Century AD.
When people learn English, they often ask why we have so many different names for the same thing. One reason is that after 1066 and all that, the Normans were the masters and the Anglo Saxons the serfs. We can see that specifically in the names of animals: cow is the animal (from Kuhe in German) and beef is the meat (from boeuf in French), The serfs cared for the animal and the masters ate them.
Since English is part of the Western Germanic language family,
It has to be either Dutch or German.
The language most closely related to English is probably Australian then American, despite many people viewing these as one and the same thing they are very differant in many ways, differant enough to be classed as seperate languages.
The spelling, punctuation and grammar of all three is differant and specific to the country of use, and despite them begining to converge in some sense through their common usage on the internet there are still many words and sayings used in one which are alien or uncomon to the others.
Geordie would be a dialect where some words are pronounced differently, with a few local ways of saying things or names. Both Australian and American are completely different languages due to having their own rules on spelling, grammar and syntax
Although there are plenty of Latin and other derivatives, German I believe is English's Mother Tongue.
german..english is derived from anglo saxon
If you mean what language is most closely related to Oxford English, then the American, Canadian, Australian versions and the like are the closest.
If you want the history of the English language, it is an Indo European language that evolved from the west Germanic languages of Anglo Saxon and Fresian infused with the common language spoken by English people lving in north eastern England after the retreat of the Romans . Over the centuries it has been influenced by Celtic, Latin, French and Scandinavian to name but a few.
If you live in London today you would not be sure what English is.
Today English is the official language of 53 countries and the following :-
European Union (one of)
Commonwealth of Nations
clearly german although celtic latin and french have made their mark on the English language