On 5/18/2014 10:05 AM, H. van der Meer wrote:

Sorry if this question reaches you twice, but the first time I used an
email address not registered with this newsgroup.

The short example below typeset with

\usemodule[mathml]
\starttext
\typebuffer
\blank
\processxmlbuffer
\stoptext

and "ConTeXt ver: 2014.04.04 00:08 MKIV beta" shows that the <mtext>
element does not honour the tags within. This severely restricts the
presentation.

So what makes you think these tags should be recognized and interpreted as being 'bold'?

see: http://en.wikipedia.org/wiki/MathML

Presentation MathML

....

Note however that these token elements may be used as extension points, allowing markup in host languages. MathML in HTML5 allows most inline HTML markup in mtext, and

<mtext><b>non</b> zero</mtext>

is conforming, with the HTML markup being used within the MathML to mark up the embedded text (making the first word bold in this example).