BEGIN;

ALTER TABLE languages DROP COLUMN english_name;
ALTER TABLE languages DROP COLUMN self_name;

CREATE TABLE language_names (
--  name         type      constraints
    id           BIGSERIAL PRIMARY KEY,
    lang_id      BIGINT    NOT NULL REFERENCES languages (id),
    name_lang_id BIGINT    NOT NULL REFERENCES languages (id),
    value        VARCHAR   NOT NULL,

--  CONSTRAINT name               CHECK (condition)
    CONSTRAINT value_is_sane_text CHECK (is_sane_text(value))
);

CREATE UNIQUE INDEX languages_lang_name_lang
    ON language_names (lang_id, name_lang_id);

COMMIT;