What app to download onto iPad 3/4 to use a US-International keyboard for English and Spanish simultaneously?

I am learning Spanish, and finding online learning extremely helpful on my iPad. I love my Logitech Ultrathin keyboard cover, and my 3/4, or ‘new’ iPad is absolutely up to the requirements of my learning app, designed for kids 6 to 8 years old through adults of any age. But I need to be able to go back and forth between the two languages every minute or two, and the “shift” + “ctrl” then + space bar toggling through the emoji, English, and Spanish keyboards each time is prohibitively cumbersome and time consuming.

I would like a US-International option for the iPad, but there isn’t one in the list provided, which seems like a big oversight. One should certainly be added in the very next update, as many people are learning new languages (finally) on their devices now that the speech recognition software has allowed it to be so helpful for this purpose. In the meantime, what app does the community recommend that I download to my iPad so I can learn to communicate with my Spanish only speaking customers faster? It feels quite urgent to me. They are lovely, kind people, and I want to be able to provide them with the best, fast customer service possible. I am good at learning language, and it is only the technology that is slowing me down. I can’t afford a new, dedicated Spanish-English keyboard at this time, and it really shouldn’t be necessary.

Thanks everyone!