Each consonant group contains seven to nine consonants. First comes the plosive consonants in four combinations of voiceless and voiced versions, and unaspriated and aspirated. Then follows a nasal consonant. Then the fricative consonants in voiceless and voiced versions. In the end we have the flapped, the uvular plosive, and the semi-vowels. In all: 40 consonants.
All the vowels come in two versions in the script: full vowel and vowel sign. The vowel sign is much simpler than the full vowel. It is used when a vowel follows a consonant. If a vowel follows another vowel, or if a words starts with a vowel, the full vowel is used. The is no pronunciation differences between full vowels and vowel signs.
The vowel signs are written next to the preceding consonant. Some vowel signs are written before, some after, some below, and some above the consonant. And one vowel sign is simply not written at all: the absense of a sign is the sign itself!
If two or more consonants are following each other, then the consonants are not written in full. Instead they "melt together" and form a new symbol. Some of these symbols are easy to recognize. However, some are very different from the full versions of the consonants.
Hindi uses the same punctuation marks as English, except for the full
stop which is represented by a vertical line.
Hindi is closely related to Urdu. The grammar of Hindi and Urdu is for the most part identical. However, Urdu draws upon Persian words for its vocabulary, and Urdu is written in Arabic-Persian script.