§ 1. Bases of election system

Members of the Riigikogu* shall be elected in free elections on the basis of a general, uniform and direct right to vote, by secret ballot.

§ 2. General right to vote

(1) An Estonian citizen with the right to vote who has attained eighteen years of age by election day has the right to vote.

(2) An Estonian citizen with the right to vote who has attained twenty-one years of age by election day and is proficient in Estonian pursuant to the level provided for in § 2¹ of this Act may run as a candidate for member of the Riigikogu.
(15.12.98 entered into force 17.01.99 - RT I 1999, 1, 1)

§ 2¹. Language requirements

The oral and written knowledge of Estonian of a member of the Riigikogu shall enable him or her to participate in the work of the Riigikogu, which means:

1) to understand the content of legislation and other texts;

2) to present reports on agenda items and express his or her opinion in the form of a speech and a comment;

3) to make inquiries, pose questions and make proposals;

4) to communicate with electors, respond to appeals and petitions, and answer inquiries.
(15.12.98 entered into force 17.01.99 - RT I 1999, 1, 1)

§ 26. Nomination of candidates

(1) Every Estonian citizen with the right to vote who meets the requirements provided for in § 2 of this Act may be nominated as a candidate in Riigikogu elections.

(12) Upon nomination, the following shall be appended to the standard application form for nomination of a candidate or candidate list:

1) the standard format consent of the candidate certified by his or her signature for his or her nomination and running as a candidate in the corresponding electoral district in the nominator's list or as an independent candidate, and confirmation that the candidate is proficient in Estonian pursuant to the level provided for in § 2¹ of this Act;
(17.11.98 entered into force 24.11.98 - RT I 1998, 102, 1678)

Source: Estonian Legal Translation Centre
http://www.legaltext.ee/indexen.htm