retext example does not work as expected w.r.t. remark example

retext-stream-example.js

var unified = require('unified');
var createStream = require('unified-stream');
var parse = require('rehype-parse');
var rehype2retext = require('rehype-retext');
var rehype2remark = require('rehype-remark');
var remarkStringify = require('remark-stringify');
var retextStringify = require('retext-stringify');
var english = require('retext-english');

// Why does the following (2remark) work (output MD)
//
// var processor = unified()
//   .use(parse)
//   .use(rehype2remark)
//   .use(remarkStringify);
//
// .. but this (2retext) does NOT work (not outputting text)

var processor = unified()
  .use(parse)
  .use(rehype2retext, unified()
    .use(english)
	)
  .use(retextStringify);

process.stdin.pipe(createStream(processor)).pipe(process.stdout);

// `TypeError: Cannot read property 'length' of undefined at nlcstToString..`


// Ran as
// curl https://example.com 2>/dev/null | node retext-stream-example.js

// Also: why is the additional `unified().use(english)` needed for retext?