Grimm's Law describes a sound change that occurred between proto-Indo-European and proto-Germanic, in which voiceless stops became voiceless fricatives, and voiced stops became voiceless stops. This sound change means that roots in Germanic languages such as English, German, and Swedish have many different consonants from corresponding roots in other Indo-European (IE) languages such as Latin, Greek, Russian, and Hindi.
voiced stops include b, d, and g
voiceless stops include p, t, and k
voiceless fricatives include f, th, and h
b becomes p and p becomes f
d becomes t and t becomes th
g becomes k and k becomes h
Example Roots
Greek pod corresponds to English foot
Russian tri corresponds to English three
Latin quod corresponds to English what