Bug 205876 "Preview","Description" on Chart Sample View are not externalized.
"Preview" and "Description" label on Chart Sample View are not externalized so they are dislayed in English. Please check the attached screen shot for detail. I think its hard coded in ChartExamples.java.
chart/org.eclipse.birt.chart.examples/src/org/eclipse/birt/chart/examples/view/ChartExamples.java
createTree( sGroup );
		
		Composite rComp = new Composite( mainComposite, SWT.NONE );
		GridData gridData = new GridData( GridData.FILL_VERTICAL
				| GridData.FILL_HORIZONTAL );
		gridData.horizontalSpan = 2;
		rComp.setLayout( new GridLayout( ) );
		rComp.setLayoutData( gridData );
		
		Group preGroup = new Group( rComp, SWT.NONE );
		preGroup.setLayout( new GridLayout( ) );
		preGroup.setLayoutData( new GridData( GridData.FILL_VERTICAL
				| GridData.FILL_HORIZONTAL ) );
		preGroup.setText( "Preview" ); 
		gridData = new GridData( GridData.FILL_VERTICAL
				| GridData.HORIZONTAL_ALIGN_FILL );
		preGroup.setLayoutData( gridData );
		paintCanvas = new Canvas( preGroup, SWT.BORDER );
		paintCanvas.setLayoutData( new GridData( GridData.FILL_BOTH ) );
		paintCanvas.setBackground( Display.getDefault( )
				.getSystemColor( SWT.COLOR_WHITE ) );
		preview = new ChartPreview( );
		paintCanvas.addPaintListener( preview );
		paintCanvas.addControlListener( preview );
		preview.setPreview( paintCanvas );
		
		Group desGroup = new Group( rComp, SWT.NONE );
		desGroup.setLayout( new GridLayout( ) );
		gridData = new GridData( GridData.FILL_HORIZONTAL );
		gridData.heightHint = 60;