Marydoll is right, she'll love songs, especially action songs. There are some lovely books with very few words too. Have a look at the Emily Gravett books like 'Orange, Pear, Apple, Bear' and her 'Bear and Hare' stories, all beautifully illustrated by the author.
If I was looking for one item to teach lots of language I'd use one of the Maisy books by Lucy Cousins - Maisy's House, which is a pop-up and flap book based on Maisy and her house, complete with a model of Maisy to play with. There are different rooms, so your DGD can learn the names of rooms, the furniture and objects as she plays with Maisy. She has a wardrobe of clothes to dress her in and to learn the names of the garments.
Two weeks is a short time, but what a fabulous opportunity for you all. Hope you have a lovely time! My DGS is bilingual and it's such an amazing skill to have.