mark-fl
You can go to Backend >> Extensions >> Language(s) >> Overrides and add new override for these language constants:
T4_LOAD_MORE = "Load more..."
T4_LOADMORE_END_MSG = "All items"
TPL_T4_PAGINATION_LOADMORE = "Load more"
TPL_T4_PAGINATION_INFINITIVE = "Infinitive load"
I added a sample for 'T4_LOAD_MORE':