Instead of using == to compare character vectors, use strcmp.
val = app.Country_Select.Value;
if strcmp(val,'Jordan')
idx = 1;
elseif strcmp(val,'Brazil')
idx = 2;
else
idx = 9;
end
app.SpokenLanguageEditField.Value = data{idx,1}.languages;
== compares element-by-element, i.e., character-by-character in this case since you're comparing character vectors, so the number of elements must be the same, i.e., the character vectors must be the same length. If the character vectors are not the same length, as in 'Niger' == 'Jordan', you'll get the error you got.
You could also use switch/case.
val = app.Country_Select.Value;
switch val
case 'Jordan'
idx = 1;
case 'Brazil'
idx = 2;
otherwise
idx = 9;
end
app.SpokenLanguageEditField.Value = data{idx,1}.languages;
