Learn Dutch: Hij zal strakjes wel aankomen. - He will probably arrive shortly.

In Dutch, certain adjectives and adverbs can take a diminutive ending, usually -jes. These are called adverbial diminutives. They don't mean a "small thing" like noun diminutives do; instead, they soften the meaning, making the manner more gentle (like zachtjes) or the time frame feel shorter and more casual (like strakjes or eventjes).

What is the exact difference in meaning between straks and strakjes?

Strakjes feels a bit softer, friendlier, or more immediate than straks (later / shortly). It translates well to "in a little bit" or "very shortly." You will often hear it used in casual contexts, especially to reassure someone.

Why is wel used here, and how does it translate to "probably"?

In this sentence, wel is a modal particle used to express a reassuring assumption. When combined with zal (will), the phrase zal wel means "will probably" or "I assume he will." It softens the statement and tells the listener not to worry about his arrival.

Why isn't the separable verb aankomen split up here?

The sentence uses the auxiliary verb zal (will). In Dutch, auxiliary verbs push the main verb to the very end of the clause in its full, unseparated infinitive form (aankomen). If it were in the present tense without zal, it would split: Hij komt strakjes wel aan.