بـ — with, by, in, and at

The one-letter preposition بـ is written onto its host. Its central everyday uses present an instrument, means, medium, price, or accompanying circumstance: بالقلم “with a pen,” بالمترو “by metro,” بالعربي “in Arabic,” and بعشرين جنيه “for twenty pounds.” It also belongs to lexical frames such as مهتم بـ “interested in.”

English translations vary among with, by, in, at, and sometimes no preposition at all. The useful generalization is not a list of glosses: بـ relates an event or state to the means, channel, or circumstance through which it holds. Its spelling follows the attached-clitic rules.

Rule 1: بـ attaches to the instrument or means

Use بـ for the object, transport, or medium used to carry out an action. It joins the following noun in writing.

مع is different: it introduces an accompanying participant or item, not an instrument. Compare فتحت العلبة بالمفتاح “I opened the box with the key” and رحت مع صاحبي “I went with my friend.” A person can be an assistant, but ordinary accompaniment still uses مع.

A spatial scene with an instrument

The card is contained في المكنة, the button is the endpoint of pressure على الزر, and the finger is the instrument بصباعي. One physical scene can require three different prepositions because each relation is different.

Rule 2: language, medium, price, and manner use stored بـ phrases

Egyptian uses بـ for a language or medium of expression, a price paid, and many manner adverbials.

Other common fixed expressions include بالليل “at night,” بالراحة “gently/slowly,” and بالظبط “exactly.” Do not infer that بـ is the general Egyptian word for English at or in. Ordinary “in the house” is في البيت, not بالبيت in the mainstream Cairo baseline.

The suffix paradigm: بيـ plus a bound pronoun

With pronouns, بـ uses forms beginning بيـ. First-person بيا has a doubled /y/; the other common forms have long ī.

Plural بيكم bīkum also occurs in conservative spelling and more MSA-influenced styles. The everyday house form here is بيكو bīku (informal).

Rule 3: lexical predicates keep بـ

Several common predicates require بـ even when English uses a different preposition:

The same اتصل بـ frame remains stable in professional speech and ordinary conversation; changing the audience does not license deleting its preposition.

Rule 4: do not confuse prepositional بـ with verbal بـ

The same written letter also marks the ordinary Egyptian imperfect. Verbal بـ attaches to a verb; prepositional بـ attaches to a noun or pronoun. A sentence can contain both.

The first and third بـ are imperfect markers on كتب and راجع. The second and fourth are prepositions in بالقلم and بالليل. Host type, not the English translation, tells you which morpheme you have.

Rule 5: relatives keep بـ plus a suffix

English strands with: “the pen I wrote with.” Egyptian normally resumes the head noun with بيه or بيها inside the relative clause.

Register and agency

بواسطة “by means of” is useful in official or technical writing (formal), but it is unnecessarily heavy in ordinary conversation when attached بـ is enough. Conversely, English passive by the technician does not automatically become بالفني. Mainstream Egyptian often uses an active clause: الفني صلح الجهاز “the technician fixed the device.” Formal Arabic may use من قبل for an agent (formal).

Alexandrian, Delta, Upper Egyptian, Bedouin, class, age, and community varieties may differ in suffix vowels or preferred fixed expressions (regional: Egypt). Ordinary Cairo retains the attached spelling across these uses.

Common Mistakes

Key Takeaways

• Attached بـ commonly marks an instrument, means, medium, price, or stored circumstance.
• Distinguish instrumental بـ from accompaniment مع and from the homophonous imperfect marker.
• Learn lexical frames such as مهتم بـ، مقتنع بـ، اتصل بـ whole.
• Suffixed بيا، بيه، بيها، بيهم stay attached, including in relative clauses.