Gradual repetition (شيئاً فشيئاً)

Distributive Repetition

To express an action happening gradually across a sequence—like "street by street," "house by house," or "group by group"—Arabic simply repeats the noun.

Both instances of the repeated noun must be in the indefinite accusative case (typically ending in ـاً). This repeated noun phrase functions as an adverb, describing the manner in which the action unfolds.

Expressing "Little by Little"

To express that a change or action is happening "little by little" or "gradually," Arabic repeats the word شيء (thing).

In this specific phrase, the two indefinite accusative nouns are joined by the particle ف (and/so), resulting in the fixed expression شيئاً فشيئاً.