Which language for a Sales Appointment Reminder app?



I’m new to codeacademy and just been dipping my toe in up til now. But one of our sales engineers came to me with an idea for an app which made me focus my thinking.

You see we’re not a big company, so the powers-that-be have decided they’re not yet ready to invest in a CRM system. The sales engineers are left to manage their call schedules in whatever way they think is best - whether that’s outlook, excel or a paper diary!

What my sales engineer is after is an app to remind him when it’s time to book an appointment with each customer. Different customers require different levels of looking after. Some need to be seen weekly, some monthly, others only 6 monthly. When he’s busy with big projects with the main customers it can be easy to forget to schedule visits with the smaller ones. The app should have the following features:

1.) Allocate a visit frequency to each customer (weekly, monthly, every x months, etc)
2.) Raise a reminder when the next visit is due
3.) Keep a list of the reminders until a visit is actually booked
4.) Once a visit has happened, reschedule the next one

So which do you think is the best language to create this sort of app? It would be used on iphone.