Future Perfect and Past Conditional in Welsh

In Brief

Welsh forms the future perfect with a future form of bod (“to be”) + wedi + a verb-noun: Bydda i wedi gorffen erbyn tri means “I will have finished by three.” The past conditional, also called the conditional perfect, uses a conditional form of bod + wedi + a verb-noun: Baswn i wedi mynd means “I would have gone.” Unlike ordinary future and conditional action phrases, these perfect forms do not put yn before the main verb.

Overview

The future perfect looks forward to a deadline and views an action as already complete at that future point. In “By three, I will have finished,” the finishing happens before three o’clock, while three o’clock is the point from which you look back. Welsh marks this completed viewpoint with wedi.

The past conditional looks back at a possible action that did not happen, or whose reality is being left open: “I would have gone,” “she would have helped,” or “would you have agreed?” It is especially useful for regrets, explanations, imagined alternatives, and third conditional sentences about an unreal past.

These are B2 combinations rather than entirely new tense systems. They bring together forms you may already know: the future and conditional of bod, and wedi for completion. A verb-noun is the basic Welsh verb form, such as mynd (“go”), gweld (“see”), or gorffen (“finish”). English calls forms such as “finished” and “gone” past participles, but Welsh keeps the verb-noun unchanged and carries the time information in bod.

How It Works

The two core patterns

Meaning	Pattern	Example
will have done	future bod + wedi + verb-noun	Bydda i wedi gorffen.
would have done	conditional bod + wedi + verb-noun	Baswn i wedi gorffen.

Compare these with the corresponding non-perfect forms:

View of the action	Welsh	English
future action	Bydda i'n gorffen.	I will finish.
completed before a future point	Bydda i wedi gorffen.	I will have finished.
imagined action	Baswn i'n gorffen.	I would finish.
imagined completed action	Baswn i wedi gorffen.	I would have finished.

The contrast between yn and wedi is essential. Yn presents the action as an activity, state, or event without marking prior completion. Wedi presents it as completed before the relevant future or imagined reference point.

Future perfect forms

The future form of bod changes for person; wedi and the verb-noun stay the same.

Person	Future perfect	English frame
I	bydda i wedi gorffen	I will have finished
you (singular, informal)	byddi di wedi gorffen	you will have finished
he / she	bydd e / hi wedi gorffen	he / she will have finished
we	byddwn ni wedi gorffen	we will have finished
you (plural or polite)	byddwch chi wedi gorffen	you will have finished
they	byddan nhw wedi gorffen	they will have finished

A future endpoint is often introduced by erbyn, meaning “by” or “by the time of”:

• erbyn tri — by three
• erbyn yfory — by tomorrow
• erbyn diwedd yr wythnos — by the end of the week
• erbyn hynny — by then

The endpoint may also be a clause (a group of words containing a verb): erbyn i chi gyrraedd means “by the time you arrive.”

Past conditional forms

The conditional forms likewise change for person while the rest of the phrase remains fixed.

Person	Past conditional	English frame
I	baswn i wedi mynd	I would have gone
you (singular, informal)	baset ti wedi mynd	you would have gone
he / she	basai fe / hi wedi mynd	he / she would have gone
we	basen ni wedi mynd	we would have gone
you (plural or polite)	basech chi wedi mynd	you would have gone
they	basen nhw wedi mynd	they would have gone

The first consonant is often soft-mutated from b to f, especially in questions, negatives, and some clause patterns: Faset ti wedi mynd? (“Would you have gone?”), Faswn i ddim wedi aros (“I would not have stayed”). You will also encounter both baswn and faswn in affirmative results. This variation does not itself change the tense.

Questions and negatives

Future questions commonly begin with a soft-mutated form:

• Fydd hi wedi gadael erbyn hynny? — Will she have left by then?
• Fyddwch chi wedi gorffen erbyn dydd Gwener? — Will you have finished by Friday?

Put ddim after the subject to make the construction negative:

• Fydda i ddim wedi gorffen erbyn tri. — I will not have finished by three.
• Fyddan nhw ddim wedi cyrraedd erbyn hynny. — They will not have arrived by then.
• Faswn i ddim wedi dewis hynny. — I would not have chosen that.
• Fasen ni ddim wedi gwybod. — We would not have known.

The order is therefore form of bod + subject + ddim + wedi + verb-noun. Do not move ddim after the main verb.

Past conditional with an if-clause

A third conditional describes an unreal past condition and its unreal result. A reliable learner pattern is:

pe + bawn-series form + wedi + verb-noun, baswn/faswn-series form + wedi + verb-noun

• Pe bawn i wedi gwybod, faswn i wedi dod. — If I had known, I would have come.
• Pe bai hi wedi gofyn, baswn i wedi helpu. — If she had asked, I would have helped.

Notice the useful division of labour: pe bawn i wedi... introduces “if I had...,” while baswn i wedi... gives “I would have....” Welsh has regional and stylistic alternatives, but keeping these two frames separate is a dependable starting point.

No extra yn after wedi

The ordinary conditional uses yn before an action: Baswn i'n mynd (“I would go”). Once wedi marks completion, yn disappears: Baswn i wedi mynd (“I would have gone”), not baswn i wedi yn mynd or baswn i'n wedi mynd.

The same rule applies in the future perfect: Bydd hi wedi gadael, not bydd hi'n wedi gadael.

Examples in Context

Welsh	English	Note
Bydda i wedi gorffen erbyn tri.	I will have finished by three.	A clear future deadline.
Bydd hi wedi gadael erbyn hynny.	She will have left by then.	The leaving precedes a future reference point.
Byddan nhw wedi cyrraedd cyn cinio.	They will have arrived before lunch.	Cyn gives the earlier limit.
Fyddwch chi wedi darllen yr adroddiad erbyn yfory?	Will you have read the report by tomorrow?	Polite or plural question.
Fydda i ddim wedi gorffen y gwaith erbyn pump.	I will not have finished the work by five.	Negative future perfect.
Erbyn i ni gyrraedd, bydd y siop wedi cau.	By the time we arrive, the shop will have closed.	The endpoint is a whole clause.
Baswn i wedi dod, ond roeddwn i'n sâl.	I would have come, but I was sick.	An unreal action followed by the real reason.
Basai hi wedi derbyn y cynnig.	She would have accepted the offer.	Imagined completed result.
Faset ti wedi dweud ie?	Would you have said yes?	Informal singular question.
Fasen ni ddim wedi ennill heb dy help di.	We would not have won without your help.	A necessary condition is expressed with heb.
Pe bawn i wedi gweld y neges, faswn i wedi ateb.	If I had seen the message, I would have replied.	Third conditional.
Pe bai hi wedi gadael yn gynharach, basai hi wedi dal y trên.	If she had left earlier, she would have caught the train.	Both events belong to an unreal past.
Bydda i wedi bod yn gweithio yma am flwyddyn erbyn mis Medi.	By September, I will have been working here for a year.	Perfect progressive: wedi bod yn gweithio.
Baswn i wedi gallu helpu pe baet ti wedi gofyn.	I would have been able to help if you had asked.	A modal verb-noun follows wedi.

Common Mistakes

Adding yn to a perfect construction

• Wrong: Bydda i'n wedi gorffen erbyn tri.
• Right: Bydda i wedi gorffen erbyn tri.
• Why: Use yn for bydda i'n gorffen (“I will finish”), but use wedi directly for prior completion.

Using a present perfect for a future deadline

• Wrong for the intended meaning: Dw i wedi gorffen erbyn yfory.
• Right: Bydda i wedi gorffen erbyn yfory.
• Why: Dw i wedi gorffen means “I have finished” now. The future form bydda i creates the future viewpoint required by “by tomorrow.”

Confusing “would do” with “would have done”

• Wrong for a missed past action: Baswn i'n dod, ond roeddwn i'n sâl.
• Right: Baswn i wedi dod, ond roeddwn i'n sâl.
• Why: Baswn i'n dod means “I would come.” Add wedi when the imagined action should already have been completed.

Using the result form mechanically after pe

• Wrong in the core third-conditional pattern: Pe baswn i wedi gwybod, baswn i wedi dod.
• Right: Pe bawn i wedi gwybod, faswn i wedi dod.
• Why: In the standard pattern taught here, pe bawn i wedi... means “if I had...,” and faswn i wedi... means “I would have....” Learn the two halves as a pair.

Putting ddim after wedi

• Wrong: Faswn i wedi ddim mynd.
• Right: Faswn i ddim wedi mynd.
• Why: In these spoken negative patterns, ddim follows the subject and comes before wedi.

Trying to make the main verb carry the tense

• Wrong: Bydd hi wedi gadawodd erbyn hynny.
• Right: Bydd hi wedi gadael erbyn hynny.
• Why: Gadael is the unchanged verb-noun. The form of bod carries person and time; Welsh does not add a finite past ending to the verb after wedi.

Usage Notes

The future perfect is most natural when the future reference point matters. Words such as erbyn (“by”), cyn (“before”), and erbyn i... (“by the time...”) make that relationship explicit. Without an endpoint, the construction can still be clear from context, but learners often produce more natural sentences by stating the relevant deadline.

English “will have” does not always require a word-for-word future perfect in Welsh, and everyday speakers may choose a simple future when completion is already obvious. Compare Bydda i'n gorffen erbyn tri (“I’ll finish by three”) with Bydda i wedi gorffen erbyn tri (“I’ll have finished by three”). The second more strongly presents three o’clock as a point at which the task will already be complete.

Forms vary across Welsh regions, registers, and teaching traditions. This article follows the spoken paradigm in the concept—bydda i and baswn i. You may also see fuller written future forms such as byddaf and conditional alternatives such as byddwn or buaswn. Likewise, pronouns vary, including e, fe, and northern o for “he.” Recognise these alternatives, but keep one consistent paradigm in your own practice until the core timing contrast feels automatic.

The past conditional often implies that the event did not happen: Baswn i wedi dod, ond... normally introduces why the speaker did not come. In a question, however, the answer may be unknown: Faset ti wedi derbyn y swydd? asks about an imagined choice rather than asserting what happened.

Beyond the Basics / Advanced Use

Perfect progressive sequences

To express “will have been doing” or “would have been doing,” place bod yn + verb-noun after wedi:

• Bydda i wedi bod yn aros am awr. — I will have been waiting for an hour.
• Baswn i wedi bod yn gweithio yno ers blynyddoedd. — I would have been working there for years.

The sequence may look long, but each part has one task: bydda/baswn sets the future or hypothetical viewpoint, wedi marks prior completion or accumulated duration, and bod yn gweithio supplies “be working.”

Modal and passive combinations

A modal verb-noun can follow wedi just like any other verb-noun:

• Baswn i wedi gallu aros. — I would have been able to stay.
• Basai hi wedi gorfod gadael. — She would have had to leave.

Completed passive meanings can also be embedded in the construction:

• Bydd y gwaith wedi cael ei orffen erbyn dydd Gwener. — The work will have been finished by Friday.

Here cael ei orffen is the passive phrase (“be finished”), and bydd ... wedi places its completion before Friday.

Mixed time reference

Not every conditional sentence keeps both clauses in the same time. A past condition can have a present result:

• Pe bawn i wedi derbyn y swydd, baswn i'n byw yng Nghaerdydd nawr. — If I had accepted the job, I would be living in Cardiff now.

The pe bawn i wedi clause points to the unreal past decision. The result uses baswn i'n byw, not baswn i wedi byw, because living in Cardiff is imagined as true now, not as a completed past event. Choosing between yn and wedi is therefore a choice about viewpoint, not simply a reaction to the word pe.

Shortened expressions of regret

The result may be left unsaid when it is obvious:

• Pe bawn i wedi gwybod! — If only I had known!

The listener supplies the missing consequence from context—perhaps “I would have come” or “I would have acted differently.” This is a natural reminder that conditional patterns serve real conversational purposes, not only complete textbook sentences.

Practice Tips

1. Build deadline pairs. Start with a simple future such as Bydda i'n gorffen yfory, then add a viewpoint: Bydda i wedi gorffen erbyn deg yfory. Say what must be complete and by when.
2. Practise matched contrasts. Use one verb in four frames: bydda i'n mynd, bydda i wedi mynd, baswn i'n mynd, baswn i wedi mynd. Translate each one only after deciding whether it is future or imagined, and ongoing/simple or already complete.
3. Reconstruct missed events. Take a real reason—Roeddwn i'n sâl—and create an unreal alternative: Baswn i wedi dod, ond roeddwn i'n sâl. Then expand it into Pe na bawn i wedi bod yn sâl, faswn i wedi dod (“If I had not been ill, I would have come”).

Related Concepts

• Prerequisite: Conditional Mood — introduces the baswn, baset, basai, basen, and basech forms.
• Useful foundation: Compound Tenses — explains how bod, wedi, newydd, and yn combine to express viewpoint.
• Useful foundation: Bod — Future Tense — provides the future forms used in bydda i wedi....
• Next step: Complex Conditionals — develops third and mixed conditional patterns with pe bawn i wedi....