import { AuditoryDescription } from './auditory_description';
import { Span } from './span';
import { SsmlRenderer } from './ssml_renderer';
export declare class SsmlStepRenderer extends SsmlRenderer {
    private static CHARACTER_ATTR;
    private static MARKS;
    markup(descrs: AuditoryDescription[]): string;
    merge(spans: Span[]): string;
}
