speak English

According to what i've learnt,
In english , words are connected ,

e.g
There's ocean's in between us , is pronounced"
THer zOuS.n sin bitwi:n^s.

But ,how come that sometimes this rule doesn't apply,
for example , I've heard native say "speak English ",
and they don't pronounce it as ( spi: kingliS )
because they make a stop right before "english",
and I've notice this happens many times ,
so I just liked to know if this stop happens before a
determined vowel or if there's a way to know when not
to attach words .

I guess it has something to do with the word being stressed or not. In your first example, both words are unstressed, while in "speak English", the first syllable of "English" is stressed, therefore you instinctively make a glottal stop before it. (By the way: it shouldn't be 'ocean's',but 'oceans').

is it not true that all languages are spoken in this way in quick everyday speech, ie without a pause inbetween each word?

Yes, all languages show changes in connected speech. This is one reason why phonetic transcription is so useful in learning a language: the way words sound in isolation is often very different from the way they sound in complete sentences and paragraphs.