From Wikipedia: http://en.wikipedia.org/wiki/Gurmukh%C4%AB_alphabet

The Gurmukhi alphabet contains thirty-five letters. The first three are distinct because they form the basis for vowels and are not consonants, and except for æṛa are never used on their own. See the section on vowels for further details.

The pronunciation of ਵ will vary between v and w depending on the word.ਙ |ŋɑŋːɑ̃ | and ਞ |ɲəɲːɑ̃ | are rarely used. They cannot begin a syllable or be placed between two consonants, and occur most often as an allophone of n before specific consonant phonemes.

• à – grave accent = tonal consonant.

• To differentiate between consonants, the Punjabi tonal consonants kà, chà, ṭà, tà, and pà are often transliterated in the way of the Hindi voiced aspirate consonants gha, jha, ḍha, dha, and bha respectively, although Punjabi does not have these sounds.
• Tones in Punjabi can be either rising or falling; in the pronunciation of Gurmukhi letters they are falling, hence the grave accent as opposed to the acute.

In addition to these, there are six consonants created by placing a dot (bindi) at the foot (pair) of the consonant (these are not present in Sri Guru Granth Sahib). These are used most often for loanwords, though not exclusively:

|ləlːɑ pɛɾ bɪnd̪i| was only recently added to the Gurmukhi alphabet. Some sources may not consider it a separate letter.

“Subjoined” letters

Three “subscript” letters are utilised in Gurmukhi: forms of ਹ(h), ਰ(r), and ਵ(v). ਰ(r) and ਵ(v) are used to make consonant clusters and behave similarly; subjoined ਹ(h) raises tone.

• Subjoined ਰ(r): For example, the letter ਪ(p) with a regular ਰ(r) following it would yield the word ਪਰ pər (“but”), but with a subjoined ਰ would appear as ਪ੍ਰ- (prə-), resulting in a consonant cluster, as in the word ਪ੍ਰਬੰਧ (prəbə́nd̪, “management, government”)

• Subjoined ਵ(v): somewhat less common in modern usage. For example, ਸ followed by a regular ਵ would yield ਸਵ– (səv-) as in the word ਸਵੇਰ (səvēr, “morning”), but with a subjoined ਵ would produce ਸ੍ਵ (svə-) as in the word ਸ੍ਵਰਗ (svərəg, “heaven”)

• Subjoined ਹ(h): behaves the same way as the regular ਹ(h) in non-word-initial positions. The regular ਹ(h) is pronounced at the beginning of words but not in other positions, where it instead raises the tone. The difference in usage is that the regular ਹ is used after vowels and the subscript version when there is no vowel, and is attached to consonants.
  • For example: the regular ਹ is used after vowels as in ਮੀਹ (transliterated as mih, to show tonality, mī́, “rain”). The subjoined ਹ(h) acts the same way but instead is used under consonants: ਚ(ch) followed by ੜ(ṛ) yields ਚੜ (chəṛ), but not until the rising tone is introduced via a subscript ਹ(h) does it properly spell the word ਚੜ੍ਹ (chə́ṛ, “climb”).

Vowels

Gurmukhi is similar to Brahmi scripts in that all consonants are followed by an inherent ‘a’ sound (unless at the end of a word when the ‘a’ is usually dropped). This inherent vowel sound can be changed by using dependent vowel signs which attach to a bearing consonant. In some cases, dependent vowel signs cannot be used – at the beginning of a word or syllable for instance – and so an independent vowel character is used instead.

Independent vowels are constructed using three bearer characters: Ura (ੳ), Aira (ਅ) and Iri (ੲ). With the exception of Aira (which represents the vowel ‘a’) they are never used without additional vowel signs.

Dotted circles represent the bearer consonant. Vowels are always pronounced after the consonant they are attached to. Thus, Sihari is always written to the left, but pronounced after the character on the right.

Vowel examples

Nasalisation: tippi and bindi

Ṭippi ( ੰ ) and bindi ( ਂ ) are used for producing a nasal phoneme depending on the following obstruent or a nasal vowel at the end of a word. All short vowels utilise ṭippi and all long vowels are paired with bindi except for Dulankar ( ੂ ) which uses ṭippi instead . Older texts may not follow these conventions.

The aforementioned bindi ( ਂ ) is also used for nasalisation.

Gemination: addak

The use of addak ( ੱ ) indicates that the following consonant is geminate. This means that the subsequent consonant is doubled or reinforced.

Halant

The halant (੍) character is not used when writing Punjabi in Gurmukhi. However, it may occasionally be used in Sanskritised text or in dictionaries for extra phonetic information. When it is used, it represents the suppression of the inherent vowel.

The effect of this is shown below:

ਕ – kə

ਕ੍ – k

Visarg

The visarg symbol (ਃ U+0A03) is used very occasionally in Gurmukhi. It can either represent an abbreviation (like period is used in English) or it can act like a SanskritVisarga where a voiceless ‘h’ sound is pronounced after the vowel.

Udaat

The udaat symbol (ੑ U+0A51) occurs in older texts and indicates a high tone.

Numerals

Gurmukhi has its own set of numerals that behave exactly as Hindu-Arabic numerals do. These are used extensively in older texts. In modern contexts, they have been replaced by standard Latin numerals.