Compound Prepositions in Welsh

In Brief

Welsh compound prepositions are multi-word expressions that do the job of one English preposition: wrth ymyl “next to,” o flaen “in front of,” y tu ôl i “behind,” ar ben “on top of,” and o gwmpas “around.” Learn each expression as a complete unit, including any mutation already inside it: blaen becomes flaen in o flaen, for example. Put the expression before the place or object: Mae'r caffi wrth ymyl y siop means “The café is next to the shop.”

Overview

A preposition is a word such as “in,” “on,” or “behind” that shows how one thing relates to another. A compound preposition does the same job with a group of words. Welsh uses these expressions constantly when describing streets, rooms, buildings, maps, and the positions of people and objects.

This is an A1 grammar point because the beginner pattern is straightforward: say what is located, then add the compound preposition and the reference place. In Mae'r banc o flaen yr orsaf, “The bank is in front of the station,” y banc is the thing being located and yr orsaf is the reference point.

English and Welsh divide up space in slightly different ways. An English learner may be tempted to translate “behind” or “in front of” one word at a time, but that produces incomplete Welsh. It is more reliable to store y tu ôl i and o flaen as single vocabulary items. The words inside them have their own meanings and mutation history, but the whole expression is what you need in conversation.

How It Works

The basic location pattern

The normal present-tense pattern uses mae (“is/are” for a third-person subject):

Mae + thing being located + compound preposition + reference point.

• Mae'r ysgol wrth ymyl y parc. — The school is next to the park.
• Mae'r car o flaen y tŷ. — The car is in front of the house.
• Mae'r ardd y tu ôl i'r tŷ. — The garden is behind the house.

A noun phrase is a noun together with words that belong to it, such as “the shop,” “a large house,” or “my old car.” The reference point can therefore be longer than one word: wrth ymyl y siop fach (“next to the small shop”) and y tu ôl i'r hen westy (“behind the old hotel”).

Do not insert yn before these location phrases. Welsh uses yn in sentences such as Mae'r car yn goch (“The car is red”), but a prepositional location follows the subject directly: Mae'r car o flaen y tŷ.

The five core expressions

Welsh expression	Main English meaning	Structural point
wrth ymyl	next to, beside	Treat both words as one expression.
o flaen	in front of	The base word blaen appears with soft mutation: b → f.
y tu ôl i	behind	Keep the final i before the reference point.
ar ben	on top of	The base word pen appears with soft mutation: p → b.
o gwmpas	around	The base word cwmpas appears with soft mutation: c → g.

The soft mutation is a change to the first consonant of a word after certain triggers. Here it is already built into three expressions. Say and write o flaen, ar ben, and o gwmpas, not o blaen, ar pen, or o cwmpas. At beginner level, memorising the finished expression is easier than rebuilding it from separate words.

Articles and nouns after the expression

Welsh has the definite article y, yr, 'r, corresponding to English “the,” but no ordinary indefinite article corresponding to “a/an.” Compare:

• wrth ymyl y siop — next to the shop
• wrth ymyl siop — next to a shop
• o flaen y tŷ — in front of the house
• o flaen tŷ mawr — in front of a large house

Do not assume that a mutation inside the compound expression also mutates the following noun. In o flaen tŷ, the f of flaen belongs to the fixed expression; tŷ remains tŷ.

There may still be a mutation for an independent reason. A feminine singular noun can undergo soft mutation after the article: tref (“town”) becomes y dref (“the town”), so the concept example is o gwmpas y dref. The change t → d comes from the article plus the noun's gender, not from o gwmpas.

Why y tu ôl i needs special attention

The final i is part of the construction:

• y tu ôl i'r car — behind the car
• y tu ôl i'r ysgol — behind the school
• y tu ôl i dŷ — behind a house

Before the article, i + y/yr appears as i'r. With no article, i can trigger soft mutation in the next word, so car can become gar: y tu ôl i gar (“behind a car”). This is the same mutation behaviour that learners meet with the simple preposition i.

To ask about a location, put ble (“where”) first:

• Ble mae'r orsaf? — Where is the station?
• Mae hi wrth ymyl y banc. — It is next to the bank.
• Ble mae'r allweddi? — Where are the keys?
• Maen nhw ar ben y llyfr. — They are on top of the book.

Welsh uses the singular verb form mae with a named plural subject such as yr allweddi in the question. In the answer, the plural pronoun nhw gives maen nhw.

Position, movement, and viewpoint

These expressions are not limited to static sentences with mae. They can follow movement verbs too:

• Cerddon ni o gwmpas y dref. — We walked around the town.
• Rhedodd y ci o gwmpas y parc. — The dog ran around the park.
• Cerdda o flaen y car. — Walk in front of the car.

“Front” and “behind” depend on a viewpoint. O flaen y tŷ normally means on the front side of the house; y tu ôl i'r tŷ means on its back side. With people, vehicles, queues, or movement, the direction they face may determine front and back.

It is also useful to distinguish contact from separation. Ar ben normally presents something as on the top or highest part of something else. For “above” without contact, Welsh commonly uses uwchben instead. A lamp can be ar ben y bwrdd if it stands on the table, but uwchben y bwrdd if it hangs above it.

Examples in Context

Welsh	English	Note
Mae'r gwesty wrth ymyl yr orsaf.	The hotel is next to the station.	A common directions pattern
Mae caffi wrth ymyl y banc.	There is a café next to the bank.	caffi has no indefinite article
Mae'r safle bws o flaen y siop.	The bus stop is in front of the shop.	o flaen is kept as a unit
Mae'r bws yn aros o flaen yr ysgol.	The bus is waiting in front of the school.	The phrase follows a verb-noun construction
Paid â gadael y bag o flaen y drws.	Don't leave the bag in front of the door.	A practical instruction
Mae'r ardd y tu ôl i'r tŷ.	The garden is behind the house.	Keep the final i
Mae'r plant y tu ôl i'r car.	The children are behind the car.	i + yr becomes i'r
Mae Siân y tu ôl i mi.	Siân is behind me.	i mi is the pronoun form “to me”
Mae'r gath ar ben y wal.	The cat is on top of the wall.	Position on the top edge
Mae'r castell ar ben y bryn.	The castle is on top of the hill.	A higher geographical position
Mae'r allweddi ar ben y llyfr.	The keys are on top of the book.	Two objects in contact
Cerddon ni o gwmpas y dref.	We walked around the town.	Movement around an area
Mae pawb yn eistedd o gwmpas y bwrdd.	Everyone is sitting around the table.	People arranged on different sides
Ble mae'r fferyllfa? Mae hi wrth ymyl y swyddfa bost.	Where is the pharmacy? It is next to the post office.	A short directions exchange

Common Mistakes

Translating “behind” without the final i

• Wrong: Mae'r garej y tu ôl y tŷ.
• Right: Mae'r garej y tu ôl i'r tŷ.
• Why: The complete expression is y tu ôl i. The i is not optional in the standard beginner pattern, and it combines with the article as i'r.

Undoing a mutation inside the expression

• Wrong: Mae'r car o blaen y tŷ.
• Right: Mae'r car o flaen y tŷ.
• Why: O triggers soft mutation here, changing blaen to flaen. Learn the complete form o flaen. The same principle gives ar ben and o gwmpas.

Adding yn before a location phrase

• Wrong: Mae'r siop yn wrth ymyl y banc.
• Right: Mae'r siop wrth ymyl y banc.
• Why: The compound preposition already links the shop to its location. It does not need the linking particle yn in front of it.

Treating un as an automatic word for “a”

• Wrong: wrth ymyl un siop when you simply mean “next to a shop”
• Right: wrth ymyl siop
• Why: Welsh normally has no indefinite article. Un means “one” and is used when the number matters or receives emphasis; it is not a routine replacement for English “a/an.”

Confusing “on” with “on top of”

• Wrong choice: ar ben y wal when you only mean a picture is “on the wall”
• Better: ar y wal — on the wall
• Why: Ar ben highlights the top, highest point, or upper surface. Use simple ar for a general “on” relationship.

Mutating every noun after a compound preposition

• Wrong: o flaen dŷ for “in front of a house”
• Right: o flaen tŷ
• Why: The mutation in flaen does not automatically spread to the next noun. A following noun changes only if another rule triggers it, as tref → y dref after the article with a feminine singular noun.

Usage Notes

Wrth ymyl is a clear choice for two things directly beside or very close to each other. Welsh ger and gerllaw can express the broader idea “near,” so “next to” and “near” should not always be treated as identical.

Ar ben is more specific than simple ar. In everyday descriptions, use it when the top matters: ar ben y bryn (“on top of the hill”), ar ben y bwrdd (“on top of the table”). If something is higher but not resting on the reference object, uwchben (“above”) is usually clearer.

You will encounter both y tu ôl i and the shorter-looking tu ôl i in modern Welsh. The version in this concept, y tu ôl i, is a dependable full form to learn first. Spoken Welsh also varies in its reinforcing pronouns—southern fe and northern fo, for example—but the spatial construction itself remains recognisable.

English often uses the same phrase for a place and for an approximate time. Welsh o gwmpas can likewise be understood as “around” in contexts such as o gwmpas pump o'r gloch (“around five o'clock”), although its concrete spatial use is the best starting point.

Beyond the Basics / Advanced Use

You do not need to master the following patterns at A1, but recognising them will make later Welsh much easier.

When the reference point is a pronoun such as “me” or “them,” i uses forms related to conjugated prepositions:

English	Welsh after y tu ôl
behind me	y tu ôl i mi
behind you (singular)	y tu ôl i ti
behind him	y tu ôl iddo fe/fo
behind her	y tu ôl iddi hi
behind us	y tu ôl i ni
behind you (plural or polite)	y tu ôl i chi
behind them	y tu ôl iddyn nhw

Other compound prepositions may use a possessive construction instead. A possessive is a word such as “my” or “your.” For example, “in front of me” can be o fy mlaen i, often contracted to o'm blaen i. Here fy (“my”) causes a nasal mutation, changing blaen to mlaen. You may similarly meet wrth fy ymyl i (“beside me”) and o fy nghwmpas i (“around me”). These forms combine the compound preposition with the wider Welsh systems of possessives, mutations, and optional reinforcing pronouns.

The five expressions also develop figurative meanings:

• Pwy sydd y tu ôl i'r cynllun? — Who is behind the plan?
• Roedd hi o flaen pawb arall. — She was ahead of everyone else.
• Ar ben hynny, roedd hi'n hwyr. — On top of that, it was late.
• Roedd pobl o'i gwmpas. — There were people around him/her.

These are natural extensions of the spatial meanings. Notice that advanced pronoun forms and possessive mutations may appear even when no physical location is involved.

Practice Tips

1. Build a five-place map. Draw a house, shop, park, car, and café. Describe every relationship aloud with Mae...: Mae'r caffi wrth ymyl y parc; mae'r car o flaen y tŷ. Move the objects and repeat.
2. Learn expressions, not isolated words. Put o flaen, ar ben, o gwmpas, wrth ymyl, and y tu ôl i on flashcards as complete chunks. Say each one with a noun phrase so that the final i in y tu ôl i is never lost.
3. Practise contrasting pairs. Ask Ble mae...? and answer with opposites or close contrasts: o flaen / y tu ôl i, ar / ar ben, and wrth ymyl / ger. This prevents an English word such as “on” or “near” from controlling every choice.

Related Concepts

• Prerequisite: Simple Prepositions — introduces i, o, ar, wrth and the mutation patterns used inside these expressions.
• Next step: Location with Bod — combines location phrases with mae, questions with ble, and everyday place vocabulary.
• Later development: Conjugated Prepositions — explains forms such as iddo, iddi, and iddyn nhw when a preposition refers to a person.