The Germanic languages

Sound system
All Germanic languages have undergone some common sound changes:

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  First Germanic Sound Shift (Grimm’s Law)
  Jacob Grimm was one of the great linguists of the 19th century. He found evidence for the unity of all the modern Germanic languages in the phenomenon known as the First Germanic Sound Shift (also known as Grimm’s law ), which set the Germanic branch apart from the other branches of the Indo-European family. This shift occurred before the 7th century when records started to be kept. According to Grimm’s law, the shift occurred when /p, t, k/ in the classical Indo-European languages (Latin, Greek, and Sanskrit) became/ f, t, h/ in Germanic languages. For example, Latin pater > English father, Latin cornu > English horn.
  
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  Second Germanic consonant shift (High German consonant shift)
  The Second consonant shift took place probably beginning between the 3rd-5th centuries AD, and was almost complete before the earliest written records in the High German language were made in the 9th century. It occurred in High German (spoken in mountainous areas) which gave rise to today’s Standard German. Low German dialects were not affected by the Second Consonant Shift.
  
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  Here are some examples: classical Indo-European /k, t, p/ became /h, th, f/ in English and /h, d, f/ in German. For example, Latin frater > English brother and German Bruder.
  classical Indo-European /g, d, b/ became /k, t, p/ in English and /kh, ts, f/ in German. For example, Latin decem > English ten and German zehn.
  

Vowels

Most modern Germanic languages have a large inventory of vowel phonemes consisting of 14-16 vowels. Vowel length typically distinguishes word meaning, and there is a contrast between rounded and unrounded front vowels in many of the Germanic languages.

Consonants

Modern Germanic languages have fairly similar consonant systems consisting of 20-22 phonemes.

Stress

All Germanic languages are characterized by a shift of stress to the root and later to the first syllable of the word. Though English has an irregular stress pattern, native words always have a fixed stress, regardless of what is added to them. In addition, some Germanic languages have a pitch accent, e.g.,Norwegian and Swedish).