Analysis of information sources in references of the Wikipedia article "Japanese grammar" in English language version.
The murkiness surrounding the Japanese particles は (ha/wa) and が (ga) is often picked out as the most confusing area of Japanese study, and it continues to be confusing right the way through from beginner to advanced level.
Chikagoro 'dōgutachi' no yō ni mono ni 'tachi' o tsukeru koto ga mirareruga, kore wa tadashī tsukaikata to wa ienai.近ごろ「道具たち」のように物に「たち」を付けることがみられるが、これは正しい使い方とはいえない。 [These days, it can be seen that '-tachi' can be suffixed to [terms for] items, as in 'tool-tachi', but this is not a correct way to use [it].]