Is using echo rather than printf a trouble maker for string translation using .pot file and Poedit?

I was wondering could the use of echo in php code rather than the use of printf() be the cause of a .mo file or in general the reason why the translation files do not work at all?

For Example:

In my php code I have this line of code:
echo __('Twinkle Twinkle little star');

Which has the double underscore identifier __().

When using Poedit, I get my string displayed in the translatable strings column, so that's not an issue.

Sum up:
Could echo cause a problem with the translation even thought Poedit can index and understand that the string is there?

Thanks in advance for your time.

Solution

echo and printf are not related to translations. They are merely ways to output a string.

The translating is performed by the __() function. So assuming you have your locale set to French with the proper files loaded:

echo "Hello";
// Hello
echo __("Hello");
// Bonjour

printf("Hello");
// Hello
printf(__("Hello"));
// Bonjour