In Hanoi, "họ" is a very clear stop, low tone. In this recording, "họ" sounds like "ho".
In this case its not actually that important.... The subject of the sentence comes right at the start...people will be listening for a pronoun.
In the south there is a difference in pronunciation: x is pronounced like English s, s is like Russian ш and Pinyin sh.
But not everyone follows that rule it's mostly relegated to formal broadcasts.
You mean the northern Mandarin pronunciation of sh as a retroflex, with the tongue tip curled back? I wasn't aware of retroflexes in Vietnamese north or south.
Sadly no. You just have to memorise. However, even Vietnamese children have issues with s and x in kindergarten and primary schools so I assume it's an inevitable part of learning Vietnamese.
They are pronounced the same in Northern Vietnamese (and often also in the South). In many dialects in the South, though, "s" will sound like sh, while "x" will sound like s (like in the North).
Nowadays it's increasingly merged in the South. You're more likely to hear s being pronounced distinctly in the South in formal settings like on the news or from an MV/host. Most people just merge s/x together. Similarly, v is mostly just like d or gi ("y") unless it's on the news or from an MC/host (but even then it can just be "y").
Wouldnt it still be coreect to say "the books" as a plural or is the qualifier "many" necessary?