Compound Verb-Nouns in Welsh

In Brief

Welsh has many built-up verb-nouns such as penderfynu “to decide,” defnyddio “to use,” ymddiheuro “to apologise,” and ymddwyn “to behave.” Although their formation varies, they fit the same sentence frames as simpler verb-nouns: Dw i'n defnyddio... for a present action and Dw i wedi penderfynu... for a completed one. Learn each form together with the object, preposition, or second verb-noun that normally follows it.

Overview

A Welsh verb-noun (berfenw) is the basic form used to name an action. It covers much of the work done by both the English infinitive (“to use”) and the English -ing form (“using”). Simple examples include mynd “to go” and darllen “to read.” Compound or derived verb-nouns are more visibly built from a root, a prefix, an ending, or a combination of these: defnydd “use” is related to defnyddio “to use,” while cyd- “together” helps form cydweithio “to cooperate.”

At B1, the useful goal is not to take every word apart historically. It is to recognise recurring pieces and then use the finished verb-noun accurately. Some forms are transparent; others, including penderfynu, are best treated as complete dictionary words. Welsh also relies on fixed expressions with common verb-nouns such as gwneud “to do or make,” cael “to get or have,” and rhoi “to give.” These multiword expressions belong to the same practical vocabulary-building area, even though they are phrases rather than single written words.

For an English-speaking learner, two differences are especially important. First, a Welsh verb-noun does not normally contain a word corresponding to English “to”: penderfynu aros means “to decide to stay,” with two verb-nouns side by side. Second, English often uses a reflexive pronoun where Welsh simply uses a lexical verb beginning in ym-: ymddwyn means “to behave,” not a word-for-word “to behave oneself.”

How It Works

The same frames as other verb-nouns

A compound verb-noun does not acquire a special conjugation. In the most common spoken patterns, bod “to be” carries the person and time, while the verb-noun itself remains unchanged.

Frame	Welsh example	Meaning
bod + yn + verb-noun	Dw i'n defnyddio'r ap.	I use / am using the app.
negative bod + ddim yn + verb-noun	Dw i ddim yn defnyddio'r ap.	I do not use / am not using the app.
bod + wedi + verb-noun	Mae hi wedi penderfynu.	She has decided.
bod + newydd + verb-noun	Maen nhw newydd gydweithio.	They have just worked together.
mynd i + verb-noun	Dyn ni'n mynd i ailystyried.	We are going to reconsider.
one verb-noun after another	Ceisia ganolbwyntio.	Try to concentrate.

The yn in Dw i'n defnyddio is a verbal particle: a small linking word that introduces the ongoing or general action. After a vowel it contracts to 'n. Do not insert it after wedi or newydd. The verbal yn normally leaves the initial consonant unchanged, so it is yn defnyddio, not yn ddefnyddio.

English present simple and present continuous often share this one Welsh frame. Depending on context, Mae e'n defnyddio'r cyfrifiadur can mean “He uses the computer” or “He is using the computer.” Time words clarify the intended meaning: bob dydd “every day” suggests a habit, while ar hyn o bryd “at the moment” suggests an action in progress.

Common building patterns

The label “compound” covers several useful kinds of built-up vocabulary. These patterns are clues, not rules for inventing any verb you want.

Pattern	Welsh forms	Meaning	What to notice
root or noun + -u / -io	defnydd → defnyddio	use → to use	-io is productive, but spelling must be learned.
adjective or root + -hau	glân → glanhau	clean → to clean	The ending often has a “make or become” sense.
ail- “again”	ailystyried	to reconsider	The action is done or considered again.
cyd- “together”	cydweithio	to cooperate	The participants act jointly.
cam- “wrongly”	camddeall	to misunderstand	The action is performed incorrectly.
ym-	ymddiheuro, ymddwyn	to apologise, to behave	The meaning may be self-directed, mutual, or simply lexical.

Modern Welsh also forms many everyday verbs with -io, including forms connected with borrowed vocabulary, such as ffonio “to phone.” A visible ending can help you recognise a verb-noun, but it does not tell you everything about its syntax (how it connects to the other words in a sentence).

The prefix ym-

The prefix ym- occurs in many verbs involving the subject’s own action, interaction between people, or engagement in an activity. Compare ymolchi “to wash oneself,” ymgyfarfod “to meet one another,” and ymarfer “to practise.” With d, the written result is often ymdd-, as in ymddwyn and ymddiheuro.

However, ym- is not an automatic translation of English self or each other. Dw i'n ymddiheuro is already a complete “I apologise”; no separate word for “myself” is needed. Conversely, you cannot add ym- freely to an ordinary verb and assume that the result will be a real Welsh word. Learn ym- forms as vocabulary, using the prefix only as a memory aid.

Learn what follows each verb-noun

The next word is often less predictable than the verb’s internal formation. A direct object (the person or thing directly affected by an action) follows defnyddio without a preposition. Ymddiheuro, by contrast, normally uses i for the person and am for the reason. An adjective describing the manner of ymddwyn follows adverbial yn.

Welsh pattern	English	Note
defnyddio rhywbeth	to use something	Direct object: no preposition.
penderfynu gwneud rhywbeth	to decide to do something	A second verb-noun follows directly.
ymddiheuro i rywun	to apologise to someone	i introduces the person.
ymddiheuro am rywbeth	to apologise for something	am introduces the reason.
ymddwyn yn dda / yn wael	to behave well / badly	This yn turns the description into a manner expression.
cydweithio â rhywun	to cooperate with someone	â introduces the other participant.

Notice yn dda, where da “good” undergoes a soft mutation (a regular change to the first consonant) and becomes dda. This adverbial yn is separate from the verbal yn before ymddwyn: Mae'r plant yn ymddwyn yn dda contains both.

Fixed expressions with gwneud, cael, and rhoi

Welsh often packages an action as a common verb-noun plus a noun or phrase. English does this too in “make a decision,” “have a chat,” and “give an answer,” but the natural combinations do not always match word for word.

Welsh expression	Natural English	Literal cue
gwneud penderfyniad	to make a decision	make + decision
gwneud defnydd o rywbeth	to make use of something	make + use + of
cael sgwrs	to have a conversation	get/have + conversation
cael cyfle i wneud rhywbeth	to get a chance to do something	get + opportunity
rhoi cynnig ar rywbeth	to try something	give + attempt + on
rhoi'r gorau i rywbeth	to give something up	fixed idiom; learn as a unit

These expressions do not replace the single-word verbs in every context. Penderfynu is the direct everyday way to say “decide,” while gwneud penderfyniad presents the decision more explicitly as an event or choice. Treat the phrase as one lexical unit and record its preposition as part of it.

Examples in Context

Welsh	English	Note
Dw i wedi penderfynu mynd.	I have decided to go.	penderfynu followed directly by mynd.
Dyn ni wedi penderfynu aros tan yfory.	We have decided to wait until tomorrow.	Completed decision with wedi.
Mae e'n defnyddio'r cyfrifiadur.	He is using the computer.	Direct object after defnyddio.
Dw i ddim yn defnyddio'r car bob dydd.	I do not use the car every day.	Negative present or habitual action.
Wyt ti'n gallu defnyddio'r peiriant hwn?	Can you use this machine?	defnyddio follows gallu.
Dw i'n ymddiheuro am yr oedi.	I apologise for the delay.	am gives the reason.
Ymddiheurodd hi i'r cwsmer.	She apologised to the customer.	Formal or written inflected past.
Mae'r plant yn ymddwyn yn dda heddiw.	The children are behaving well today.	Verbal yn, then adverbial yn dda.
Roedden nhw'n ymddwyn yn wael yn y dosbarth.	They were behaving badly in class.	Past ongoing or habitual frame.
Mae'r ddwy adran yn cydweithio'n agos.	The two departments work closely together.	cyd- carries the idea of joint action.
Dylem ni ailystyried y cynllun.	We should reconsider the plan.	ail- adds the idea of “again.”
Mae'n hawdd camddeall y neges.	It is easy to misunderstand the message.	cam- signals an incorrect understanding.
Cawson ni gyfle i ymarfer Cymraeg.	We had a chance to practise Welsh.	Fixed cael cyfle i pattern.
Rho gynnig arni cyn penderfynu.	Give it a try before deciding.	Idiomatic rhoi cynnig ar.

The table includes both conversational long forms, such as Mae e'n defnyddio, and a more compact inflected form, Ymddiheurodd hi. The vocabulary remains the same, but the surrounding grammar changes with tense and register.

Common Mistakes

Adding English “to” before a second action

• Wrong: Dw i wedi penderfynu i fynd.
• Right: Dw i wedi penderfynu mynd.
• Why: After penderfynu, the next verb-noun normally follows directly. English “decide to go” does not require a separate Welsh equivalent of “to.”

Putting yn after wedi

• Wrong: Mae hi wedi yn penderfynu aros.
• Right: Mae hi wedi penderfynu aros.
• Why: Wedi introduces the verb-noun itself. The verbal particle yn belongs to a different frame and is not used here.

Translating prepositions word for word

• Wrong: Dw i'n ymddiheuro i'r camgymeriad.
• Right: Dw i'n ymddiheuro am y camgymeriad.
• Why: Apologise i a person but am a reason or event. Learn the whole patterns ymddiheuro i rywun and ymddiheuro am rywbeth.

Adding a reflexive pronoun to every ym- verb

• Wrong: Dw i'n ymddwyn fy hun yn dda. when you simply mean “I behave well.”
• Right: Dw i'n ymddwyn yn dda.
• Why: Ymddwyn already has the lexical meaning “behave.” Welsh does not need to copy the English expression “behave myself.” Fy hun can be used for deliberate emphasis, but it is not part of the basic verb.

Confusing the two uses of yn

• Wrong: Mae e'n ymddwyn da.
• Right: Mae e'n ymddwyn yn dda.
• Why: The first 'n introduces the verb-noun; the second yn creates the manner phrase “well” and causes da → dda.

Inventing forms from a productive pattern

• Wrong approach: adding -io or ym- to any English or Welsh root and assuming the result exists.
• Better approach: check a dictionary, then learn the attested verb-noun in a short sentence.
• Why: Word-building patterns help with recognition, but vocabulary remains conventional. A grammatically possible-looking form may be rare, regional, or nonexistent.

Usage Notes

Welsh varies by region and register. Spoken forms of bod differ — for example, learners may hear Dw i, Rydw i, or other regional forms — but the compound verb-noun remains stable. Likewise, northern and southern speakers may choose different surrounding vocabulary without changing the basic patterns yn + verb-noun and wedi + verb-noun.

Single-word forms and light-verb phrases can differ in emphasis. Defnyddio'r adnoddau is the ordinary “use the resources”; gwneud defnydd o'r adnoddau is closer to “make use of the resources” and can sound more deliberate or formal. Prefer the expression you have actually encountered rather than replacing every simple verb with gwneud, cael, or rhoi.

Some derived verbs are everyday conversational vocabulary, while others occur more in formal writing. The inflected past Ymddiheurodd hi is natural in written narrative, but speech often uses a periphrastic form (a multiword verb construction), depending on dialect and context. Recognition of both styles is more important at B1 than forcing every verb into a literary-looking form.

Beyond the Basics / Advanced Use

In compact past constructions with an inflected form of gwneud, the following verb-noun commonly undergoes soft mutation: Wnes i benderfynu aros “I decided to stay,” where penderfynu becomes benderfynu. This mutation comes from the grammatical construction, not from the fact that the verb-noun is compound. Compare the perfect Dw i wedi penderfynu, where the initial p remains unchanged.

Verb-nouns can also behave more like nouns after prepositions: ar ôl penderfynu “after deciding,” cyn defnyddio'r peiriant “before using the machine,” and heb ymddiheuro “without apologising.” When a pronoun is the understood object, written Welsh often places a possessive form before the verb-noun, as in cyn ei ddefnyddio “before using it.” The initial mutation can then help show which possessive construction is present. This system is worth recognising, but it is best studied separately rather than guessed from English.

Finally, productive prefixes can stack with familiar vocabulary. If ystyried is “to consider,” ailystyried is “to reconsider”; if deall is “to understand,” camddeall is “to misunderstand.” Even here, meaning and usage are lexical: a prefix narrows the possibilities, but a dictionary and real examples confirm the actual word.

Practice Tips

1. Learn a frame, not an isolated translation. Record defnyddio rhywbeth, penderfynu gwneud rhywbeth, and ymddiheuro i rywun am rywbeth. This prevents most object and preposition errors.
2. Build three time-frame sentences. For each new verb-noun, make a present sentence with yn, a completed sentence with wedi, and a future plan with mynd i: Dw i'n defnyddio..., Dw i wedi defnyddio..., Dw i'n mynd i ddefnyddio....
3. Sort vocabulary by visible pieces. Keep short lists for ym-, ail-, cyd-, cam-, and -io, but verify every item. Then listen for each complete form rather than trying to translate its pieces while speaking.

Related Concepts

• Prerequisite: Verb-Nouns — introduces the basic berfenw and the bod + yn construction.
• Useful next step: Perfect and Recent Past — develops the wedi and newydd frames used with these verb-nouns.
• Useful next step: Past Tense with Gwneud — explains forms such as Wnes i benderfynu and the mutation after gwneud.
• Advanced connection: Inflected Verb Forms — helps you recognise compact forms such as Ymddiheurodd hi in writing.