How to call parametrized function from Visualforce?

You cannot pass parameters to method bindings made in your Visualforce page to your controller, as per the help topic here, you can only provide 'action', 'get' and 'set' methods.

In order to implement your requirement I would recommend you consider looking at Visualforce Components, such that you can have something like

 <c:myOutputText myValue="test"/>
 <c:myOutputText myValue="{!MyObject__c.MyFieldToFormat__c}"/>

This component would internally use the apex:outputText component as above, however its controller would have been passed the 'test' value as an attribute to the component. On the controller you would have a getFormattedValue to output the formatted version.

<apex:component controller="MyOutputTextController">
  <apex:attribute name="myValue" type="String" description="Value to format" assignTo="{!myValueAttr}"/>
  <apex:outputText value="{!formattedValue}"/>
</apex:component>

It wouldnt be possible to do this - you can only invoke getters or action methods.

A workaround would possible be to have javascript (or an actionFunction) invoked, which can invoke controller methods via js-remoting and pass in parameters, you would then have to use javascript to replace text on the VF Page.

As an aside, if the text to be displayed is known when the page renders, you could just include the formatting in your getter, so that your getter returns formatted text ? The visualforce doesn't have to be aware of the need for formatting?