Afghanland.com: In 5000 BC  there were 2 different languages categorized

All languages are categorized into 2 major groups (Indo European and Proto European)

DARI

Dari دری Darī, pronounced daer ree) in historical terms refers to the persian court language of the Sassanids. In essence, Middle Persian is similar to Dari while Farsi was the slang language of the countryside. The modern Persian spoken in Iran is a dialect of Pahlavi. Dari is the name given to the New Persian literary language at a very early age and was widely used in Arabic and Persian texts. Scholars believe that Dari refers to the Persian word dar or darbār meaning "Court", as it was the formal language of the Sassanids. The original meaning of the word dari according to ibn muqaffa, is the language of the cities of Madā'en; it is spoken by those who are at the king’s court.

PASHTO

Pashto is spoken in the Southern , South eastern Provinces of Afghanistan, Pashtu could possibly be the ancestors all Hebrew Languages, and the language of the lost tribes of Israel. 8% of 150 million in Pakistan speak Pashto and 35% of 27 million in Afghanistan. 12 milllion in Pakistan and 9.45 million in Afghanistan with  total of 21.45 million pashto speakers on each side of the Durrand Line. Pashtuns are sometimes compared with the Pakhta tribes mentioned in the Rigveda (1700–1100 BC), apparently the same as a people called Pactyans, described by the Greek historian Herodotus as living in the Achaemenid's Arachosia Satrapy as early as the 1st millennium BC. However, this comparison appears to be due mainly to the apparent, etymologically unjustified, similarity between their names

UZBAKI

Uzbaki is spoken by 1 Million Turkmens and 300 thousand of those speak Turkmani. Uzbek is a language which can be considered the direct descendant or a latter form of Chagatay, the language of great Turkic Central Asian literary development in the realm of Chagatai Khan, Timur (Tamerlane), and the Timurids. The language was championed by Mir Ali-Sher Nawa'i in the 15th and 16th centuries. Ultimately based on the Qarluq variant of the Turkic languages, it contained large numbers of Persian and Arabic loan-words. By the 19th century it was rarely used for literary composition.

Others

Other major languages Includes Baluchi modern Nooristani.

The Major Languages of Afghanistan are Pashto and Dari where an Afghan is familiar with at least one of these languages. Even thought there are over 60% pashtoons in Afghanistan, less than a third speak Dari.

Pashto 35%, Dari 50%, Turkic languages (primarily Uzbek and Turkmen) 11%, 30 minor languages (primarily Balochi and Pashai) 4%, much bilingualism

Source:Afghanland.com and CIA world fact book