Prepositions in Welsh behave very differently from how they work in English.

Instead of just placing a pronoun after a preposition, the preposition itself actually changes its ending to match the person.

Grammarians call these “inflected prepositions” or “conjugated prepositions”.

It really just means that a word like “to” changes slightly when you say “to me”, “to you”, or “to them”.

Here’s a straightforward breakdown of how they work in everyday spoken Welsh.

What is an inflected preposition

In English, prepositions are static words like “on”, “with”, “to”, and “for”.

When you pair them with a person, you just stick a pronoun at the end, like “on me” or “for you”.

In Welsh, you can’t simply put a basic preposition next to a pronoun.

If you take the Welsh word for “on” (ar) and the word for “me” (fi), you don’t say ar fi.

Instead, the word ar absorbs the pronoun and grows a personal ending, becoming arna i.

This happens with almost every common preposition in the Welsh language.

It works very similarly to how verbs conjugate in languages like Spanish or French.

How to inflect prepositions in Welsh

To build an inflected preposition, you need three simple parts.

First, you take the base preposition, which often expands into a slightly longer stem.

Second, you attach a personal ending to that stem.

Third, in spoken Welsh, you usually add the matching pronoun right after it for clarity.

In very formal written Welsh, people often drop the pronoun at the end because the ending already tells you who’s being talked about.

However, in everyday spoken Welsh, you should always include the pronoun.

Here are the basic endings you’ll see attached to the stems in spoken Welsh:

The three main families of prepositions

Most inflected prepositions in Welsh fall into one of three groups based on the vowel they use in their endings.

Once you recognize these patterns, memorizing them becomes much easier.

The ‘A’ family

Prepositions in this group use the vowel a in the first and second person singular (“me” and “you”).

The most common examples are ar (on), am (for/about), and at (to/towards).

Notice how ar gains an extra “n” to become the stem arn- before adding the endings.

Here’s how they look in natural sentences.

The ‘O’ family

Prepositions in the ‘O’ family use the vowel o for the “me” and “you” forms instead of a.

Common prepositions in this group include heb (without), rhwng (between), and yn (in).

Note that when yn (in) is inflected, its stem changes to yndd-.

The ‘T’ family

This is a smaller group where a t sound is added to the stem.

The main prepositions here are wrth (by/to) and dros (over/for).

The most common inflected prepositions

By far, the most important inflected preposition to learn first is i (to / for).

You’ll hear and use this constantly in Welsh, as it’s used to say things like “I have to” (mae’n rhaid i mi) or “thank you” (diolch i chi).

It’s irregular, so it doesn’t neatly fit into the three families above, making it best to memorize on its own.

Notice that only the third-person forms (him, her, them) actually change the preposition i into idd-.

The others just use the normal preposition plus the pronoun.

Regional differences in North and South Wales

The biggest regional difference with inflected prepositions comes down to how you say “with” or express possession (“having” something).

In North Wales, people use the preposition gan (with/by).

In South Wales, people use gyda (with), which thankfully doesn’t inflect at all.

Because gan is used to say “I have” in the North, Northern learners must learn its inflected forms early on.

It’s also quite irregular, changing its vowel to gen in the first and second person singular.

You’ll also notice the standard pronoun difference for “him” across all prepositions.

Northern speakers always use fo (e.g., arno fo), while Southern speakers use fe (e.g., arno fe).

In some parts of South Wales, you might also hear people use e instead of fe in casual speech.

Prepositions that never change

The good news is that not every Welsh preposition needs to be inflected.

Several very common prepositions stay the exact same no matter what pronoun follows them.

The most common non-inflecting prepositions are:

• gyda (with - used mostly in the South)
• efo (with - used in the North for “accompanying”)
• fel (like / as)
• ers (since)
• tua (towards / approximately)
• trwy (through - though this can inflect, people often don’t in casual speech)

With these words, you can just drop the normal pronoun right after them, just like in English.

Summary

Learning inflected prepositions takes a little bit of practice because the concept feels unfamiliar to native English speakers.

Instead of trying to memorize every single table at once, focus on the third-person forms (-o fo/fe, -i hi, -yn nhw) first, as they’re the most consistent across all the different preposition families.

Once you get used to hearing how the endings match the pronouns that follow them, using them will start to feel like a natural rhythm in your Welsh conversations.