English and German are both members of the Germanic language family. All modern forms of these languages originated from a common ancestor language spoken in the region of modern-day Scandinavia roughy 2500 years ago. Linguists call this language Proto-Germanic. To demonstrate the similarities between these languages here are a few examples of the word apple:
apple (English), äpple (Swedish), Appel (Low German), Apfel (High German), æble (Danish)
There are two branches of modern Germanic languages: Northern and Western. The Northern branch includes Swedish, Danish, Norwegian, Faroese and Icelandic. These languages are very closely related and the countries also have strong cultural ties. The Western branch of the Germanic language family includes English, Scots, High German, Low German, Dutch and Frisian.
English is one of the world’s leading languages with 400 million mother tongue speakers on all continents and a growing number of second language speakers. While Scots shares a lot of features with English, it has a large amount of its own vocabulary and can be very difficult for English speakers to understand and is therefore generally classified as its own language. German is split into High and Low German each of which features numerous dialects. Dutch has its own variants as well, such as Flemish spoken in Belgium and Afrikaans spoken in South Africa.
Finally there is Yiddish. Most modern Yiddish speakers belong to the Eastern branch spoken by Jewish people whose ancestors lived in Eastern Europe. Although the Yiddish language was spoken by an estimated 11 million people in Europe before World War II, numbers now vary between 1.5-2,000,000 speakers worldwide. While this language shares a large vocabulary with German, there has been a shift in the pronunciation of certain vowel sounds between the languages. For example, the Yiddish pronunciation of the word apple is epl. Furthermore, modern Yiddish is written with the Hebrew alphabet whereas all other Germanic languages are written with the Roman alphabet.
For a map of Germanic languages, click here.