In what language?
I am quatrolingual (Dutch - English - French - German) and I do think without bragging I make very few mistakes in Dutch and English. I somehow get irritated when people make silly mistakes such as the classic "-dt" errors with verbs in Dutch. I can get quite irritated when people make very silly mistakes simply because of not trying to use the correct grammar or spelling.
I however still make a bit too many mistakes in German. While my German vocabulary is very good, I still mix up grammatical forms such as Dativ and Akkusativ too often. For example "bitte geben Sie mich" or "bitte geben Sie mir" ... That sort of stuff, I still make mistakes with that a bit too often. In French I tend to sometimes make errors with verbs when using past tense.
I do take pride that I still write Dutch almost errorless despite having left my native country 4 years ago. However, it all comes down to efford. Reading Dutch online papers and writing an email to my family in Belgium frequently is enough to keep my skills up to date. If only I had done that after learning Spanish: seeking a Spanish penfriend or so to keep practising it. I unfortunately didnt and as a result forgot about 90% of the Spanish I learnt
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Do what Thou wilt shal be the whole of the Law.
Love is the Law, Love under Will. And...
every man and every woman is a star
(excerpt from The Book of the Law - Aleister Crowley)
"Od lo avda tikvateinu" (excerpt from the Israeli hymn)