Mae'n bwrw glaw!

                          This is a well-known nursery rhyme

Mae'n bwrw glaw yn sobor iawn,        It's raining dreadfully
Wel dyna beth anghynnes,              That's a chilling thing (thought)
Mochal dan yr ymbarel                     Sheltering under the umbrella
A cherdded fel brenhines.                     And walking like a queen

Children's nursery rhymes often teach essential word patterns.
Line 1
Mae'n bwrw glaw = It's raining
...yn sobor iawn = quite (very) dreadfully
    
     Of course you can change sobor and use trwm (heavy) 

                Mae'n bwrw glaw yn drwm iawn = It's raining heavily


Line 2
Wel dyna beth anghynnes  ---> ! Well that's awful
                                                                              
                           Wel dyna beth ofnadwy (ofnadwy = awful)

Line 3

Mochal dan yr ymbarel   ---> Cysgodi dan yr ymbarel (Sheltering under ......)

             Mae'r ddwy ferch yn cysgodi dan yr ymbarel

Line 4

A cherdded fel brenhines  --->  And walking like a queen!
                  by using  fel (like) we're creating a comparison - e.g.

                                Canu fel aderyn  (to sing like a bird)

                  Mae Bil yn y bath yn canu fel aderyn! 
                          (Bil in the bath sings like a bird!)