Sanskrit is the most original and natural language.All the alphabets in Sanskrit are derived from nature.Nature is manifested as Kundalini inside a human being.The saying "Yatho Pinde Thatho Brahmaande" explains that complete universe is reflected inside Human being.
4 + 6 + 10 + 12 + 16 + 2 = 50
Alphabets from अ,आ,इ ई ,उ ----------- अ: are beej
mantras of Vishuddh chakra situated at Throat
Subsequent letters are from the other chakras
Agya chakra has last alphabets - ha and ksha
The beej mantras are pronounced as haM and kshaM
Finally Sahasraar has beej mantra OM