dydd Llun / nos Lun
Days of the Week
Each day is dydd (day) + a name: dydd Llun (Monday). For the evening or night, use nos instead: nos Lun (Monday night).
How It Works
The seven days
- dydd Llun Monday → nos Lun
- dydd Mawrth Tuesday → nos Fawrth
- dydd Mercher Wednesday → nos Fercher
- dydd Iau Thursday → nos Iau
- dydd Gwener Friday → nos Wener
- dydd Sadwrn Saturday → nos Sadwrn
- dydd Sul Sunday → nos Sul
The day names start with a capital letter; dydd and nos do not.
Why nos Lun changes. Nos is a feminine noun, and a word that describes a feminine noun takes soft mutation, just like cath fach (a little cat). See Adjectives After Feminine Nouns and Soft Mutation. Dydd is masculine, so the name after it never changes: dydd Llun, dydd Gwener.
Morning and afternoon. Bore (morning) and prynhawn (afternoon) are masculine too, so nothing changes after them: bore Llun (Monday morning), prynhawn dydd Gwener (Friday afternoon).
On Monday. Welsh needs no word for on. When a day is used to say when something happens, careful speech and writing give it soft mutation: Wela i di ddydd Llun (See you on Monday). In relaxed speech you will also hear dydd Llun here. See Soft Mutation in Time Phrases.
Every Friday night is bob nos Wener: pob (every) softens to bob in a time phrase.
Examples (6)
- Mae hi'n ddydd Llun heddiw.
It's Monday today.
After the linking word 'n, dydd softens to ddydd.
- Wyt ti'n rhydd nos Wener?
Are you free on Friday night?
Gwener softens to Wener after nos.
- Mae'r gêm nos Sadwrn.
The game is on Saturday night.
Sadwrn begins with s, which never mutates.
- Dw i'n mynd i'r côr bob nos Fercher.
I go to choir every Wednesday night.
- Dw i'n gweithio o ddydd Llun i ddydd Gwener.
I work from Monday to Friday.
The prepositions o and i soften dydd to ddydd.
- Wela i di ddydd Mawrth!
See you on Tuesday!
A day used as a time phrase softens: ddydd Mawrth.
Common Mistakes
Mutating the day name after dydd.
Mae'r cyfarfod dydd Lun.Mae'r cyfarfod dydd Llun.Dydd is masculine, so the name after it keeps its first letter. Only nos, which is feminine, softens the name: nos Lun.
Forgetting the soft mutation after nos.
Dewch draw nos Gwener!Dewch draw nos Wener!Nos is feminine, so Gwener loses its g after it: nos Wener.
How It Connects
Learn This First
After feminine nos the day names soften, like any word after a feminine noun.
Related Patterns
- Adjectives After Feminine Nouns
The same rule softens the day name after feminine nos.
Level 2 - Soft Mutation in Time Phrases
Why you hear ddydd Llun for on Monday.
Level 3 - am, ar, at, dan, dros, drwy, gan, heb, i, o, wrth + Soft MutationSoft Mutation After Prepositions
Why o ddydd Llun i ddydd Gwener softens.
Level 2
Words in This Pattern
Practice dydd Llun / nos Lun in Bubblegum
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