Will you help me put the icing on the cake?

What a great idea! I love it!

Here are some of my favorite words:
Indubitable (or indubitably)
Immense

Ok now I’m drawing a blank. :/
What kind of words are you going for? Adjectives, nouns, or adverbs? How about terms from the subjects she teaches – grammar, poetry, and literature? Do you want words that might describe her and her teaching, or just random (awesome) words? Does she have any favorite words that you could use? Perhaps you could ask someone to slyly steer a conversation in the direction of cool words – as an English teacher, this wouldn’t be that odd. Or you could sneak a peek at some of her teaching books – she probably has some great vocab lists, which she would recognize and understand why you chose the words you did.

Happy Birthday?

I was thinking Happy Birthday also. Since it is a birthday cake after all.

Or, is it also a congratulations cake for landing this English teaching job? Is she teaching English to people who don’t speak English? Or, teaching English in an English speaking school? Two very different subjects. I assume it is the latter, but I could be wrong. How about felicitations? Sounds sort of Shakespearean and means congratulations and the root of the word means happy in Latin I think. Felicidades is commonly used in Spanish for birthdays. You may want to look up the word to make sure it is what you want to say if you think it is a good idea.

@JLeslie Read the first sentence of the details.

@janbb Actually, it isn’t the first sentence that tells me anything, but a later sentence saying they want to write English words, I guess means it is an ESL class.

Happy birthday still sounds good to me.

serendipitous
lithe
corollary
vicissitudes
turgid
doldrums

priscan (ancient; of early times)
whelve (to cover with an upside down vessel)
hyoid (having a ‘U’ shape)

These are a small offering (from this website, but also a warning – make sure you check the definitions to see whether they fit on a birthday cake. The first one might cause offense. :)

Also, speaking as someone who has decorated many cakes, have you done anything like this before? Writing with icing always seems to take five times as much space as I think it will. The smaller the tip of your writing implement, the harder it is to keep the icing from drying as you write. Make sure that you use the right icing and tools.

To clarify: Yes, it is her birthday, but in our family, birthday cakes are always decorated with some reference to the birthday child’s likes, character or current life. She teaches non-English-speaking children. Very young ones, though, so the words she teaches them would not be a lot of fun.
It will probably say ‘Happy Birthday’ somewhere in there, @janbb :)
@RandomGirl Thanks, I like those two already! We really are looking for any words at all.
@JLeslie “felicitations”, yes, sounds good.
@marinelife “serendipitous” is great and very fitting, and I also like “corollary”
@glacial We’ve done it before, yes. Regardless, we’ll be sure to practice first. Thanks for the link, and I think we’ll include “priscan” ;)

@longgone Just know felicitations is not used commonly on cakes or in conversation. I suggested that word when I was thinking she taught English to English speaking students in secondary school.

@JLeslie Yes, that’s fine – words which aren’t commonly used are exactly what we’re looking for.

“Effervescent felicitations upon your magnificent name day!”

One of my favourite books is the Highly Selective Thesaurus for the Extraordinarily Literate. You can see a sample of the book here.

If you don’t have this book, and its companions, the Highly Selective Dictionary… and The Book of Golden Adjectives on your Kindle, get them!

My cousin and his wife had their wedding cake covered with virtues: compassionate, love, trust, patience…

You could find words in English that describe your mother.

Some possibilities:
Loving
Patient
Mother
Teacher
Educator
Kind
Giving
Swimmer
Hiker
Elderly
Young-at-heart
Passionate

@Cupcake: I’m not sure it’s the direction in which the OP was headed, but it would be really cool to do what you suggested, but use less-common synonyms. That would be a cool cake. :D

I paint my walls with a color called marzipan.

Awesome! Thank you so much for this group effort, everyone!!
@WillWorkForChocolate I love effervescent, thanks!
@Seek_Kolinahr Looks fun, browsed through it.
@Cupcake Thanks for the idea, I will do what @RandomGirl said – use uncommon synonyms for the words which describe her.
@RandomGirl Very cool, I hope.
@Dutchess_III As long as you don’t try to paint them using actual marzipan (been there, done that)