о/об/обо + Prepositional

Prepositional Topic After О

Level 2Sounds Like o/ob/obo + predložnyj

The preposition о (or its variants об/обо) is used with the Prepositional case to talk 'about' something or someone. It answers the questions О ком? (About whom?) and О чём? (About what?).

How It Works

In Russian, the standard way to say you are thinking, speaking, or writing about a topic is to use the preposition о followed by a noun or pronoun in the Prepositional case.

1. Choosing the right form:
The choice between о and об is based on pronunciation (consonant vs. vowel sounds), not just spelling.

  • о: Used before words starting with a consonant sound. This includes 'iotated' vowels (е, ё, ю, я) because they begin with a hidden consonant glide /j/ (a 'y' sound). Example: о фильме (about the movie), о языке (about the language).
  • об: Used before words starting with a pure vowel sound (а, и, о, у, э). Example: об истории (about history), об этом (about this).
  • обо: Used before specific pronoun forms starting with consonant clusters, particularly those starting with 'вс-' or 'мн-'. Examples include обо мне (about me), обо всём (about everything), обо всех (about everyone), and обо всей (about the whole... [feminine]).
  • Abbreviations (Acronyms): The rule of pronunciation over spelling strictly applies to abbreviations. If the first letter's name starts with a vowel sound, use об (e.g., МГУ is pronounced 'em-ge-u', starting with [э], so it is об МГУ). If it starts with a consonant sound, use о. For example, while the official name of the Russian letter 'С' is 'эс' (which starts with a vowel sound), the abbreviation США is traditionally pronounced using colloquial letter names ([сэ-шэ-а]), meaning the spoken abbreviation starts with a consonant sound, so it is о США.

Pronunciation Note: Because these prepositions are unstressed, о is pronounced like a short 'a' sound.

2. Pronoun Changes:
When 3rd-person pronouns (он, она, оно, они) follow simple prepositions (like о, в, на, с), an 'н' is added to the start of the pronoun itself: о нём (about him), о ней (about her), о них (about them). Note that 1st and 2nd person pronouns like я (обо мне) or мы (о нас) do not take this 'н'.

3. Possessive Pronouns:
Third-person possessive pronouns (его, её, их) do not take an added 'н'. Because iotated vowels take о, learners frequently make the mistake of writing об её or об его. The correct forms are о её and о его. Meanwhile, их starts with a pure vowel, so it correctly takes об (об их).

4. Usage Context:
The preposition о is the standard choice for formal, scholarly, or academic writing. While the preposition про (+ Accusative) also means 'about', it is more common in informal conversation or neutral everyday speech.

Examples (6)

  1. Я часто думаю о тебе.

    I often think about you.

    Word by Word: I often think about you.

    Uses 'о' because 'тебе' starts with a consonant.

  2. Мы спорили об искусстве.

    We were arguing about art.

    Word by Word: We argued about art.

    Uses 'об' because 'искусстве' starts with the vowel 'и'.

  3. Он рассказал мне обо всём.

    He told me about everything.

    Word by Word: He told me about everything.

    Uses 'обо' before the 'вс-' consonant cluster in 'всём'.

  4. Она пишет книгу о России.

    She is writing a book about Russia.

    Word by Word: She writes book about Russia.

    Uses 'о' before the consonant 'Р'.

  5. Что ты знаешь об этом?

    What do you know about this?

    Word by Word: What you know about this?

    Uses 'об' before the vowel 'э'.

  6. Мы говорили о её работе и об их планах.

    We were talking about her work and about their plans.

    Word by Word: We talked about her work and about their plans.

    Uses 'о' before 'её' (starts with a hidden /j/ consonant) and 'об' before 'их' (starts with a pure vowel 'и').

Common Mistakes

  • Using 'о' instead of 'об' before vowels.

    Я думаю о истории.
    Я думаю об истории.

    Before the vowel 'и', you must use 'об' for smoother pronunciation.

  • Using 'об' before iotated vowels (е, ё, ю, я).

    Мы говорили об языке.
    Мы говорили о языке.

    Even though 'я' is a vowel, it starts with a /j/ sound (consonant sound), so 'о' is used.

  • Using 'о мне' instead of 'обо мне'.

    Ты забыл о мне.
    Ты забыл обо мне.

    The form 'обо' is mandatory before the pronoun 'мне'.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

о/об/обо + PrepositionalLevel 2Prepositional Topic After О

Learn This First

To use 'о/об/обо' correctly, a learner must already be familiar with the endings of the prepositional case for nouns and the irregular forms of personal pronouns in oblique cases. Additionally, knowing common verbs of communication provides the necessary context for using this pattern to express 'about' something or someone.

Words in This Pattern

обобо