English to Turkish Law/Patents Law (general) vested right leaving issue

Bir vasiyetnamede (İngiltere'de yazılmış) aşağıdaki ifadeye rastladım:
I saw the text below in a testament (written in Britain):
If my wife shall die in my lifetime or after my death but before attaining a vested interest leaving issue then everything shall g oto our children who attain age of eighteen years or marry under that age such issue shall take substitution and if more than one in equal shares per sttirpes and shares of my residuary estate which such deceased wife of mine would have taken if she had survived me and attained a vested interest but so that no issue shall take whose parent is alive and so capable of taking

Google'da yaptığım araştırmaya göre, bu vasiyetlerde kullanılan standart bir hukuk jargonu. Ne yapsamda, nokta virgül vs. olmadığı için bir yerden sonra karışıyor. Yardımlarınızı rica ediyorum.
According to Google, this is a standard law jargon used in testaments and even people from USA have problem to understand. Could you simplify the text so I can understand.

Thanks