There are actually two distinct uses for sorosoro (そろそろ). The first is as an adverb representing softly, leisurely, gently, gradually, etc. The second is the one to really watch out for: that something will be done soon, in the near future, even if it has taken some time to get there.
In the first case, you could have a sentence like this:
そろそろ寝るね. (sorosoro neru ne.)
Neru = to sleep (dictionary form)
The “ne” at the end is a friendly, reflective copula.
“I’m going to sleep soon.”
This is the translation that the site I got the sentence from uses, but it’s not the only option. We could also easily use:
“About time I got some sleep, huh.”
The “huh” at the end isn’t strictly necessary, but the “ne” is used to adjust the tone in the original. I’d just keep in mind what kind of speaking style and tone the original speaker is supposed to have. This is simple enough with manga, novels, movies, anime, etc.
Sooner or Later
Now, when used more like a noun, “sorosoro” is used in one type of circumstance: time has gradually moved forward to get close to the proper time for X.
If a military commander of some sort was overseeing an operation, looking for the right time to unleash his secret weapon, he could use 「そろそろだ。」 (sorosoro da) to indicate to his top aide that it’s just about time to strike. That is, perhaps not this second – or he’d say 「今だ！」 (ima da!) (ima = right now) instead – but the time will be very soon.
If an ordinary girl or woman is out shopping with you and checks her watch and says 「もうそろそろ」(mou sorosoro), she’s indicating that it’s already (“mou”) just about time for something unspecified, but in this context, it’s well implied that the woman needs to quit with the shopping and get home. In other words, time snuck up on her; a great deal of time has already elapsed. She’s close to outright late.
Of course, she might actually be totally late, but we don’t know that. The wording is vague enough to provide a polite way to disengage from the activity and is usually accepted as such in good grace.
One Last Look at the Adverb Version
「そろそろを英語に訳すと」(sorosoro o eigo ni yakusu to)
In this case, “o” (using “wo” in kana but always pronounced simply “o”) indicates a descriptive connection between the “sorosoro” and the verb. The “ni” indicates a modifier to the verb. “Eigo” is English. “Yakusu” is for to translate (dictionary form). The “to” that ends the sentence has an eerie resemblance to the English “to” here, really. Therefore:
“To gradually translate into English”
Having done a lot of translation, I can vouch for not rushing and letting things take a natural pace. Rushing is a bad, bad idea unless you really know the subject matter, and even then it’s not a good plan. – J