The sounds would be based on "my" pronunciation, which was greatly influenced by American English. No wonder! I studied in the United States for four years back in the early sixties, thus, was immersed in an American-speaking environment almost 24 hours a day, including the time I spent watching TV.
However, I decided to include examples of strikingly different British pronunciation as well as differences in spelling. The best example that comes to mind in terms of pronunciation is "lieutenant" pronounced as /lúténant/ in AE and as /léfténant/ in BE. As I said in a previous post, this decision was based on the fact that British English is still prevalent in Portuguese schools, though things have changed quite a bit since I started teaching forty years ago, a time when AE was practically taboo.
I remember asking Judy Thompson (RE) if she had any list of words to recommend. She sent me a few links. Then Jennifer England (RE) sent me lists of her own with 1700 words organized by sounds.
And I did my own searches, "googled" a bit. I came up with Brian Kelk's English Vocabulary World Lists and EFL/ESL Basic Vocabulary Word Lists (both found in Manythings.org, an excellent website that I used for many years). And Picture Dictionary for Kids.
Then I added words from the Brian Kelk list. From there I moved to the EFL/ESL Basic Vocabulary Lists, organized by themes. Finally, to Picture Dictionary for Kids. I took words that I felt were appropriate for EFL beginners to lower intermediate students.
By the time I got to work on Jennifer's Adult Speller vocabulary lists, I had decided that my target audience would be beginners to intermediate learners of any age. (This doesn't mean that the dictionary isn't be useful to other level learners.) My word list had grown to about 3,000 words. I put a stop at the 3,500 word mark or I'd never finish.
The next step was adding the pronunciation for each word. I used many of the sounds in the Pronunciation webpages, but made some corrections and improvements. The final step was adding the most common Portuguese translation(s).
This whole task was overwhelming. "Why?", you may ask. Think of it as 3,500 multiplied by three, the number of columns. And many rows had more than one word per column. You can imagine the task of proofreading everything several times. Each time I started over, I found typos. I was going crazy! At a certain point, I forced myself to stop. I would humbly ask the users of the dictionary to let me know of any typos. Obviously, I'll edit them and create a second version. Free for those who paid for the first version.