Different menu navigation per category

Try the following

<nav id="site-navigation" class="main-navigation" role="navigation">
    <h3 class="menu-toggle"><?php _e( 'Menu', 'twentytwelve' ); ?></h3>
    <a class="assistive-text" href="#content" title="<?php esc_attr_e( 'Skip to content', 'twentytwelve' ); ?>"><?php _e( 'Skip to content', 'twentytwelve' ); ?></a>
    <?php
    //Replace it with the id/slug/name(anything you want)
    if( is_category( 'Talkative' ) ) {
        wp_nav_menu( array( 'theme_location' => 'primary', 'menu_class' => 'nav-menu', 'menu' => 'Talkative') );
    } elseif( is_category( 'Pirtek' ) ) {
        wp_nav_menu( array( 'theme_location' => 'primary', 'menu_class' => 'nav-menu', 'menu' => 'Pirtek') );
    } else {
        wp_nav_menu( array( 'theme_location' => 'primary', 'menu_class' => 'nav-menu' ) );
    }
    ?>
</nav><!-- #site-navigation -->

Haven’t tried it, but this should work.

For details check is_category() and wp_nav_menu()