Learn English – Do you take a break between words, when pronouncing

I'll elaborate a bit on Barrie's point, which is correct, if disappointing.

The problem is that English spelling was not designed for Modern English. It was designed for Middle English, a very different language. When Middle English changed its pronunciation to become Modern English, English spelling did not change. Furthermore, English borrowed many thousands of words from other languages, which were of course pronounced differently, and spelled differently still.

The result is that one has to choose between two strategies in learning English words, however they are spelled -- this is not a problem confined to the letter I -- or else figure out some way to mix them.

Either you can actually learn the historical rules about pronunciation and learn to distinguish the different kinds of word each rule applies to -- which amounts to learning some basic linguistics,

Or you can do as Barrie suggested, and memorize 2 things about every word you learn -- (1) how it's spelled and (2) how it's pronounced (Kenyon and Knott is your friend here) -- and just ignore the possible but treacherous correspondences you might suspect between Middle English or foreign spellings and Modern English pronunciations.

The second option amounts to giving up all hope of making sense of English spelling. Most native English speakers do this, which is simpler for them, since they already know the pronunciation.

Since Anglophone education systems don't teach anything about English language, they never learn any different, and many still believe there should be a simple rule for pronouncing every letter.

This issue has been dealt with by Jennifer Jenkins in her work on English as a lingua franca (ELF). She did studies to discover which elements caused the most confusion and which mattered less. In short, here's what she found:

1. There's little variation in consonant pronunciation among the world's major English dialects. ELF speakers should aim for the same pronunciation, but generally the so-called "th sounds" can be replaced by t/d or s/z. General American /r/ should be used. Avoid flapping the /t/ in words like letter. Aspirate /t/, /p/, and /k/ in initial positions (like tore but not store).
2. Do not drop consonants in consonant clusters (e.g., problem as /pabɜm/) or at the end of a syllable (e.g., top as /ta/). If you cannot produce these, it's better to add extra vowels (a schwa) in between or after than to delete consonants.
3. Vowel length is more important than vowel quality. This is not the difference between so-called long and short vowels (e.g., hop vs hope). Instead it's the actual timing length (e.g., hat vs had). The /ɜː/ vowel, as in girl or first, is also important. American or British vowels generally make no important difference.
4. In connected speech, meaningful breaks in tone units and the placement of nuclear stress are important.

Note that all of this is based on averages and tendencies.