XWPF set text language

[zecharya.com]

Hello, I would like to set the language for an XWPF document, so the end user’s 
spellcheck can correctly identify it.

For example, in the following method:

private void wordPara(XWPFDocument document, String text, boolean bold) {
        XWPFParagraph p = document.createParagraph();
        XWPFRun runCF = p.createRun();
        runCF.setBold(bold);
        runCF.setText(text);
}

I see that XWPFRun has the method getLang(), but not setLang()
What is the proper way to do this?

Thank you!