Joseph: You mentioned they’ve been around for 50 years or so. I don’t think they updated anything since. The stories don’t have any technological items or even something as simple as a ball in them – they’re very educational stories of tzaddikim and midrashim – but nothing recent.
For current conversations a vaser-treger is less relevant than a sink… However, it’s still good background info to have — but not necessarily as a starting point.
Current childrens’ books may be less educational, but include trips to the zoo, kid’s games etc.
The Yiddish itself is mostly proper Yiddish, perhaps with a slight Chabad slant, the style a bit more verbose than your average conversation (which is the case with most good writing material). The OP wrote he wants to converse with people, so I thought other books might be more relevant, at least at first. If he wanted to attend a Gemara shiur, Machanayim might be more informative.